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Combat Crawler X2

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7721 Combat Crawler X2

561 pieces in 156 part and color combinations, plus 3 minifigures.

The official piece count includes the 20 parts inside the set's minifigures, which this inventory lists separately. Spare parts are counted in neither figure.

Before you call it missing

Builders who report a missing piece often find it in one of these places. Tick each one off as you look.

Look-alike colors in this set

These parts appear in this set in two colors that are easy to confuse. If you are one short in one color, check whether it went in where the other color belongs. Each color has its own element ID in the parts list at the back of the instructions.

2 more look-alike pairs
  • Technic Plate 2 x 4 [3 Holes] Black ×6 Dark Bluish Gray ×8 Black is darker than Dark Bluish Gray.
  • Tile 2 x 2 with Groove Black ×1 Dark Bluish Gray ×1 Black is darker than Dark Bluish Gray.
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Piece checklist

Black 212 pieces

  • Antenna 1 x 4 with Rounded Top Black Part 3957a ×2
  • Brick 1 x 1 Black Part 3005 Element 300526 ×4
  • Brick 1 x 2 Black Part 3004 Element 300426 Also in Dark Bluish Gray ×3
  • Brick 2 x 4 Black Part 3001 Element 300126 ×2
  • Brick 2 x 6 Black Part 2456 Element 4181144 or 245626 ×2
  • Brick Arch 1 x 6 x 2 - Thick Top with Reinforced Underside Black Part 3307 Element 330726 ×2
  • Brick Sloped 45° 2 x 1 Triple Smooth Black Part 3048b ×2
  • Brick Sloped 45° 2 x 3 Black Part 3038 Element 303826 ×2
  • Brick Sloped 45° 2 x 8 Black Part 4445 Element 4163334 ×2
  • Brick Sloped 75° 2 x 2 x 3 [Hollow Studs] Black Part 3684 Element 4286874 or 4248065 ×1
  • Brick Special 1 x 4 with 4 Studs on One Side Black Part 30414 Element 4162443 ×2
  • Brick Wedged, Curved 16 x 4 Triple with Inner Ridges Black Part 45301 Element 4200486 ×6
  • Crane Section 4 x 12 x 3 with 8 Pin Holes Black Part 52041 Element 4513143 ×1
  • Hinge Panel 2 x 4 x 3 1/3 Locking Dual 2 Fingers Black Part 44572 Element 4193086 ×4
  • Plate 1 x 10 Black Part 4477 Element 447726 ×2
  • Plate 1 x 2 Black Part 3023 Element 302326 ×2
  • Plate 1 x 4 Black Part 3710 Element 371026 ×2
  • Plate 2 x 2 Black Part 3022 Element 302226 Also in Dark Bluish Gray ×2
  • Plate 4 x 4 Black Part 3031 Element 4243819 or 303126 Also in Dark Bluish Gray ×1
  • Plate 4 x 8 Black Part 3035 Element 303526 ×4
  • Plate Special 1 x 2 Side Handle [Free Ends] Black Part 2540 Element 4140588 or 254026 ×4
  • Plate Special 1 x 2 [Side Handle Closed Ends] Black Part 48336 Element 4225201 ×1
  • Plate Special 1 x 2 with Handles [Flat Ends / Low Attachment] Black Part 3839b Element 383926 ×2
  • Plate Special 2 x 2 with 1 Pin Hole [Split Underside Ribs] Black Part 2444 Element 244426 Also in Dark Bluish Gray ×1
  • Technic Axle 10 Black Part 3737 Element 373726 ×2
  • Technic Axle 4 Black Part 3705 Element 370526 ×5
  • Technic Axle 6 Black Part 3706 Element 370626 ×1
  • Technic Axle 8 with Stop Black Part 55013 Element 4288089 ×2
  • Technic Axle Connector with Axle Hole Black Part 32039 Element 4107081 or 3203926 ×2
  • Technic Axle and Pin Connector Angled #5 - 112.5° Black Part 32015 Element 6271346 or 4107084 ×4
  • Technic Axle and Pin Connector Perpendicular Black Part 6536 Element 6261371 or 4173668 ×3
  • Technic Axle and Pin Connector Perpendicular 3L with Centre Pin Hole Black Part 32184 Element 6276951 or 4121667 ×1
  • Technic Axle and Pin Connector Perpendicular Double Black Part 32291 Element 6280394 or 4140430 ×1
  • Technic Beam 1 x 4 Thin with Stud Connector Black Part 2825 Element 6331570 or 4107136 ×4
  • Technic Beam 1 x 5 Thick Black Part 32316 Element 4142135 or 4140429 ×6
  • Technic Beam 1 x 7 Thick Black Part 32524 Element 4495935 or 4155458 ×2
  • Technic Brick 1 x 14 [13 Pin Holes] Black Part 32018 Element 4107558 ×6
  • Technic Brick 1 x 2 with Axle Hole Type 2 [X Opening] Black Part 32064b Also in Dark Bluish Gray ×8
  • Technic Brick 1 x 6 [5 Pin Holes] Black Part 3894 Element 389426 ×2
  • Technic Brick 6 x 8 with 4 x 6 Opening Black Part 32532 Element 6448394 or 4188143 ×2
  • Technic Brick Special 2 x 2 with Pin Hole, with 2 Rotation Joint Sockets Black Part 48172 Element 6296186 or 4275826 ×1
  • Technic Disc 3 x 3 Black Part 2723 Element 4218868 or 4121619 ×2
  • Technic Link 1 x 5 Black Part 30397 Element 4140701 ×4
  • Technic Pin Long with Friction Ridges Lengthwise, 2 Center Slots Black Part 6558 Element 655826 ×46
  • Technic Pin with Friction Ridges Lengthwise and Center Slots Black Part 2780 Element 4121715 or 278026 5 spares in the box ×33
  • Technic Plate 2 x 4 [3 Holes] Black Part 3709 Element 370926 Also in Dark Bluish Gray ×6
  • Technic Plate 2 x 8 [7 Holes] Black Part 3738 Element 373826 ×2
  • Technic Rotation Joint Ball Loop with Two Perpendicular Pins with Friction Black Part 47455 Element 4272426 or 4213374 ×4
  • Tile 2 x 2 with Groove Black Part 3068b Element 306826 Also in Dark Bluish Gray ×1
  • Tile Special 1 x 2 Grille with Bottom Groove Black Part 2412b Element 241226 ×3
  • Tool Hammer / Mallet Large Black Part 4522 Element 452226 ×1
  • Turntable 4 x 4 Top, Locking Black Part 30658 Element 4142915 ×1
  • Windscreen 5 x 2 x 1 2/3 Black Part 6070 Element 6252515 or 6170820 Also in Trans-Brown ×1

Dark Bluish Gray 125 pieces

  • Brick 1 x 2 Dark Bluish Gray Part 3004 Element 4211088 Also in Black ×1
  • Brick 1 x 2 x 2 with Inside Axle Holder Dark Bluish Gray Part 3245b ×2
  • Brick Round 1 x 1 with Fins, Open Stud Dark Bluish Gray Part 4588 Element 6331222 or 6321195 ×6
  • Brick Sloped 45° 2 x 2 Dark Bluish Gray Part 3039 Element 4211054 ×1
  • Brick Sloped Inverted 45° 2 x 1 Dark Bluish Gray Part 3665 Element 4211096 ×2
  • Brick Sloped Inverted 45° 2 x 2 [Ovoid Bottom Pin, Bar-sized Stud Holes] Dark Bluish Gray Part 3660 Element 4211000 ×1
  • Brick Special 1 x 2 with Pin Dark Bluish Gray Part 2458 Element 4211087 ×8
  • Fence Spindled 1 x 4 x 2 [2 Top Studs] Dark Bluish Gray Part 30055 Element 4256495 ×3
  • Launcher, Technic Competition Cannon Flat Bottom [Complete Assembly] Dark Bluish Gray Part 57796 Element 6064131 or 4518308 ×2
  • Plate 1 x 8 Dark Bluish Gray Part 3460 Element 4210998 ×2
  • Plate 2 x 12 Dark Bluish Gray Part 2445 Element 4211067 ×2
  • Plate 2 x 2 Dark Bluish Gray Part 3022 Element 4211094 Also in Black ×6
  • Plate 2 x 6 Dark Bluish Gray Part 3795 Element 4211002 ×1
  • Plate 2 x 8 Dark Bluish Gray Part 3034 Element 4210997 ×4
  • Plate 4 x 4 Dark Bluish Gray Part 3031 Element 4243831 or 4211089 Also in Black ×2
  • Plate 6 x 6 Dark Bluish Gray Part 3958 Element 4211134 ×1
  • Plate Special 1 x 4 Offset with Bar Holes Dark Bluish Gray Part 4590 Element 6302647 or 6086709 ×1
  • Plate Special 2 x 2 with 1 Pin Hole [Split Underside Ribs] Dark Bluish Gray Part 2444 Element 4196768 Also in Black ×7
  • Technic Axle 3 with Stud Dark Bluish Gray Part 6587 Element 6587199 or 6129590 ×8
  • Technic Axle 5.5 with Stop [Rounded Short End] Dark Bluish Gray Part 59426 Element 4508553 ×2
  • Technic Axle and Pin Connector Angled #1 Dark Bluish Gray Part 32013 Element 32013199 or 6296856 ×16
  • Technic Axle and Pin Connector Perpendicular 3L with 2 Pin Holes Dark Bluish Gray Part 42003 Element 6273715 or 4210857 ×4
  • Technic Beam 1 x 11.5 Double Bent Thick Dark Bluish Gray Part 32009 Element 6271155 or 4210668 ×2
  • Technic Brick 1 x 2 - 1 x 2 Angled with Bumper Holder [Closed Front] Dark Bluish Gray Part 2991 ×4
  • Technic Brick 1 x 2 with Axle Hole Type 2 [X Opening] Dark Bluish Gray Part 32064b Also in Black ×7
  • Technic Brick 1 x 4 [3 Pin Holes] Dark Bluish Gray Part 3701 Element 4213607 or 370127 ×2
  • Technic Brick Special 2 x 2 with 10.2mm Balls [Center Mold Indention] Dark Bluish Gray Part 57908 Element 4498096 ×1
  • Technic Brick Special 2 x 2 with Ball Socket Reinforced and Axle Hole Dark Bluish Gray Part 62712 Element 4524353 or 4497254 ×4
  • Technic Brick Special 2 x 2 with Pin Hole, Rotation Joint Ball Half [Vertical Side] Dark Bluish Gray Part 48171 Element 6492115 or 6343337 ×4
  • Technic Brick Special 2 x 2 with Pin Hole, Rotation Joint Socket Dark Bluish Gray Part 48169 Element 6278974 or 4225973 ×2
  • Technic Brick Special 2 x 2 with Solid Ball and Axle Hole Dark Bluish Gray Part 57909a ×2
  • Technic Pin Connector Plate 1 x 2 x 1 2/3 [Two Holes On Top] Dark Bluish Gray Part 32530 Element 4210763 ×4
  • Technic Plate 2 x 4 [3 Holes] Dark Bluish Gray Part 3709 Element 4227398 Also in Black ×8
  • Technic Rotation Joint Disk with Pin Hole and 3L Beam Thick Dark Bluish Gray Part 44224 Element 4182751 ×2
  • Tile 2 x 2 with Groove Dark Bluish Gray Part 3068b Element 4211055 Also in Black ×1

Light Bluish Gray 100 pieces

  • Arm Mechanical with 2 Clips [Battle Droid] Light Bluish Gray Part 30377 Element 6319333 or 4211658 1 spare in the box ×1
  • Brick 1 x 3 Light Bluish Gray Part 3622 Element 4211428 ×4
  • Brick 1 x 6 Light Bluish Gray Part 3009 Element 4211393 ×1
  • Brick Round 1 x 1 Open Stud Light Bluish Gray Part 3062b Element 4211412 ×2
  • Brick Special 1 x 2 with 2 Pins, Round Pin Holes Light Bluish Gray Part 30526 Element 4211660 ×5
  • Handlebars Light Bluish Gray Part 30031 Element 4258308 ×1
  • Hinge Plate 1 x 4 Locking Dual 1 Finger Light Bluish Gray Part 44568 Element 6276045 or 4211840 ×4
  • Large Figure Weapon, Claw Hook with Axle Light Bluish Gray Part 32551 Element 4234608 ×12
  • Plate 1 x 2 Light Bluish Gray Part 3023 Element 4211398 or 3023194 ×9
  • Plate 2 x 10 Light Bluish Gray Part 3832 Element 4211462 ×2
  • Plate 2 x 2 Light Bluish Gray Part 3022 Element 4211397 ×4
  • Plate 2 x 4 Light Bluish Gray Part 3020 Element 4211395 ×2
  • Plate 2 x 6 Light Bluish Gray Part 3795 Element 4211452 or 3795194 ×1
  • Plate Special 1 x 1 with Clip Horizontal [Thick U Clip] Light Bluish Gray Part 6019 Element 4211518 ×2
  • Tap 1 x 1 with Hole in Spout Light Bluish Gray Part 4599a ×4
  • Technic Axle 3 Light Bluish Gray Part 4519 Element 4211815 ×4
  • Technic Axle Connector with Axle Hole Light Bluish Gray Part 32039 Element 4211553 ×1
  • Technic Beam 1 x 11 Thick Light Bluish Gray Part 32525 Element 4611705 or 4534910 ×6
  • Technic Beam 1 x 11.5 Double Bent Thick Light Bluish Gray Part 32009 Element 6271156 or 4234240 ×4
  • Technic Beam 1 x 7 Bent (4 - 4) Thick Light Bluish Gray Part 32348 Element 6278129 or 4211668 ×1
  • Technic Beam 3 x 5 L-Shape Thick Light Bluish Gray Part 32526 Element 4211713 ×2
  • Technic Brick 1 x 2 [1 Pin Hole] Light Bluish Gray Part 3700 Element 4211440 ×8
  • Technic Bush 1/2 Smooth with Axle Hole Semi-Reduced Light Bluish Gray Part 32123b Element 6271165 or 4211573 2 spares in the box ×5
  • Technic Driving Ring Extension, 4 Ridges Light Bluish Gray Part 32187 Element 4278756 or 4209329 ×8
  • Technic Pin 1/2 without Friction Ridges Light Bluish Gray Part 4274 Element 4274194 or 4211483 1 spare in the box ×2
  • Technic Rotation Joint Disk with Pin and 3L Beam Thick Light Bluish Gray Part 44225 Element 6671155 or 6332151 ×2
  • Tile Special 1 x 2 Grille with Bottom Groove Light Bluish Gray Part 2412b Element 4211350 ×2
  • Turntable 4 x 4 Locking Grooved Base Light Bluish Gray Part 30516 Element 4296249 ×1

Red 55 pieces

  • Animal Body Part, Barb / Claw / Tooth / Talon / Horn, Small Red Part 53451 Element 6270107 or 4568388 2 spares in the box ×10
  • Brick Special 1 x 1 with Headlight Red Part 4070 Element 407021 ×2
  • Large Figure Weapon Claw Blade, Small Red Part 57528 Element 4543162 or 4513223 ×2
  • Plate 1 x 3 Red Part 3623 Element 362321 ×4
  • Plate 2 x 2 Red Part 3022 Element 4613974 or 302221 ×1
  • Plate 2 x 3 Red Part 3021 Element 302121 ×2
  • Plate Round 2 x 2 with Axle Hole Type 1 (+ Opening) Red Part 4032a Element 403221 ×1
  • Projectile, Technic Competition Arrow, Liftarm Shaft with Hollow Black Rubber End Red Part 57028c01 Element 4504409 ×3
  • Technic Axle 2 Notched Red Part 32062 Element 4142865 ×8
  • Technic Axle Connector Ridged [with x Hole x Orientation] Red Part 6538b Element 4125189 ×2
  • Technic Beam 1 x 9 Bent (7 - 3) Thick Red Part 32271 Element 6276845 or 6188299 ×2
  • Technic Brick 1 x 2 [2 Pin Holes] Red Part 32000 Element 4179355 or 4101764 ×1
  • Technic Bush Red Part 3713 Element 6271820 or 4227155 3 spares in the box ×10
  • Technic Pin Long with Friction Ridges Lengthwise and Stop Bush [3 Lateral Holes, Big Pin Hole] Red Part 32054 Element 4140806 or 4125198 ×6
  • Tile 1 x 4 with Groove Red Part 2431 Element 243121 ×1

Yellow 30 pieces

  • Brick Round 2 x 2 with Axle Hole Yellow Part 3941 Element 614324 or 394124 ×2
  • Brick Sloped 45° 2 x 2 Yellow Part 3039 Element 303924 ×1
  • Brick Wedged, Curved 4 x 4 No Top Studs Yellow Part 47753 Element 4639061 or 4294741 ×6
  • Hinge Plate 1 x 8 Locking with Angled Side Extensions, Rounded Plate Underside, 9 Teeth Yellow Part 30407 Element 4626523 or 4294480 ×2
  • Lever Small Base with Black Lever Yellow Part 298c02 Element 74156 1 spare in the box ×2
  • Plate 1 x 2 Yellow Part 3023 Element 302324 ×7
  • Plate Special 1 x 2 Side Handle [Free Ends] Yellow Part 2540 Element 4140587 or 254024 ×3
  • Technic Beam 1 x 3 Thick Yellow Part 32523 Element 4153707 ×3
  • Technic Brick 1 x 2 with Axle Hole Type 2 [X Opening] Yellow Part 32064b ×1
  • Technic Plate 2 x 6 [5 Holes] Yellow Part 32001 Element 6038194 or 4107750 ×2
  • Tile 1 x 2 with Engraved Code for Exo-Force Yellow Part 3069bpr0073 Element 4513198 or 4507020 ×1

Blue 9 pieces

  • Technic Axle Pin with Friction Ridges Lengthwise Blue Part 43093 Element 4309323 or 4206482 ×9

Pearl Light Gray 9 pieces

  • Arm Mechanical with Clip [Thin Support] Pearl Light Gray Part 53989 Element 4494600 or 4288114 ×6
  • Hose, Ribbed 7mm D. 11L / 8.8cm Pearl Light Gray Part 78c11 Element 4495208 or 4141672 ×2
  • Technic Axle and Pin Connector, Perpendicular with Extension Pearl Light Gray Part 53586 Element 4494486 or 4286268 ×1

Trans-Neon Green 6 pieces

  • Cone 1 x 1 [No Top Groove] Trans-Neon Green Part 4589 Element 618849 or 458949 ×6

Tan 4 pieces

  • Technic Axle Pin without Friction Ridges Lengthwise Tan Part 3749 Element 4666579 or 4186017 ×4

Trans-Red 4 pieces

  • Plate 1 x 1 Trans-Red Part 3024 Element 6513963 or 6252042 ×2
  • Plate Round 1 x 1 with Solid Stud Trans-Red Part 6141 Element 6514051 or 6208450 1 spare in the box ×2

White 3 pieces

  • Brick Wedged, Curved 6 x 2 Left, Inner Ridges White Part 41748 Element 6552117 or 4160124 ×1
  • Brick Wedged, Curved 6 x 2 Right, Inner Ridges White Part 41747 Element 4160101 ×1
  • Plate 1 x 4 White Part 3710 Element 6552108 or 6548266 ×1

Trans-Neon Orange 2 pieces

  • Wave / Flame Rounded with Base Pegs Trans-Neon Orange Part 6126a ×2

Trans-Brown 1 piece

  • Windscreen 5 x 2 x 1 2/3 Trans-Brown Part 6070 Element 4204624 Also in Black ×1

[No Color/Any Color] 1 piece

  • Sticker Sheet for Set 7721-1 [No Color/Any Color] Part 60491 Element 4512827 ×1

Minifigures 3 figures

  • Ryo in Gold Armor Minifigure, checked as a whole figure ×1
  • Iron Drone / Devastator with Red Eyes Minifigure, checked as a whole figure ×1
  • Devastator with Trans-Red Torso and Red Eyes Minifigure, checked as a whole figure ×1

Tick each piece as you find it, or mark it missing.

When a piece really is missing

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