Free tool

LEGO Missing Piece Checker

Rule out the usual hiding places first. If the piece really is gone, check the set piece by piece and leave with the element ID LEGO asks for, or a link to buy the part.

ROBOLAB Team Challenge Set Version 2.5 [USB]

Checking

9794 ROBOLAB Team Challenge Set Version 2.5 [USB]

833 pieces in 165 part and color combinations.

LEGO counts 831 pieces. This inventory comes from a separate parts catalog and lists 833; the two do not always count the same elements, so their totals differ. 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.

Show

Piece checklist

Black 315 pieces

  • Arm Grab Jaw Black Part 4221 Element 422126 ×4
  • Arm Piece with Pin, 2 Fingers Black Part 6048a Element 604826 ×2
  • Brick 1 x 2 Black Part 3004 Element 300426 ×20
  • Brick 1 x 4 Black Part 3010 Element 301026 ×6
  • Brick 2 x 2 Black Part 3003 Element 4103587 or 300326 ×20
  • Brick 2 x 2 Corner Black Part 2357 Element 235776 or 235726 ×4
  • Brick 2 x 4 Black Part 3001 Element 300126 ×25
  • Brick 2 x 6 Black Part 2456 Element 4181144 or 245626 ×6
  • Brick 2 x 8 Black Part 3007 Element 6037390 or 300726 ×8
  • Brick Round 2 x 2 with Axle Hole Black Part 3941 Element 614376 or 614326 ×8
  • Brick Sloped 45° 2 x 1 with Bottom Pin Black Part 3040b Element 4121966 or 304026 ×12
  • Brick Sloped Inverted 33° 3 x 2, Connections between Studs, Ovoid Bottom Pin Black Part 3747b Element 4500458 or 374726 ×4
  • Brick Sloped Inverted 45° 2 x 1 Black Part 3665 Element 366526 ×4
  • Hinge Plate 1 x 2 with 3 Fingers [Hollow Studs] Black Part 4275b Element 427526 ×2
  • Hinge Tile 1 x 2 1/2 with 2 Fingers on Top Black Part 4531 Element 453126 ×2
  • Hose, Ribbed 7mm D. 8L / 6.4cm Black Part 78c08 Element 4297965 ×4
  • Plate Round 1 x 1 with Solid Stud Black Part 6141 Element 614126 ×2
  • Plate Round 2 x 2 with Rounded Bottom [Boat Stud] Black Part 2654 Element 4617551 or 4278359 ×2
  • Plate Special 1 x 1 with Clip Horizontal [Thick U Clip] Black Part 6019 Element 601976 or 601926 ×2
  • Plate Special 1 x 1 with Clip Vertical [Thick U Clip] Black Part 4085c Element 408526 ×2
  • Rubber Band Small 13mm (Square Cross Section) Black Part 71509 Element 4141606 or 4107153 ×4
  • Technic Axle 10 Black Part 3737 Element 373726 ×4
  • Technic Axle 12 Black Part 3708 Element 370826 ×2
  • Technic Axle 2 Notched Black Part 32062 Element 4109810 or 3206226 ×10
  • Technic Axle 4 Black Part 3705 Element 370526 ×7
  • Technic Axle 6 Black Part 3706 Element 370626 ×8
  • Technic Axle 8 Black Part 3707 Element 370726 ×7
  • Technic Beam 1 x 7 Thin Black Part 32065 Element 6271573 or 6253293 ×4
  • Technic Beam 1 x 9 Bent (6 - 4) Thick Black Part 6629 Element 6279881 or 4119800 ×4
  • Technic Beam 2 x 4 L-Shape Thick Black Part 32140 Element 6271825 or 4120017 ×2
  • Technic Brick 1 x 10 [9 Pin Holes] Black Part 2730 Element 273026 ×8
  • Technic Brick 1 x 12 [11 Pin Holes] Black Part 3895 Element 389526 ×6
  • Technic Brick 1 x 16 [15 Pin Holes] Black Part 3703 Element 370326 ×6
  • Technic Brick 1 x 2 [1 Pin Hole] Black Part 3700 Element 370026 ×12
  • Technic Brick 1 x 4 [3 Pin Holes] Black Part 3701 Element 370126 ×10
  • Technic Brick 1 x 6 [5 Pin Holes] Black Part 3894 Element 389426 ×8
  • Technic Brick 1 x 8 [7 Pin Holes] Black Part 3702 Element 370226 ×8
  • Technic Pin Long with Friction Ridges Lengthwise, 2 Center Slots Black Part 6558 Element 655826 ×8
  • Technic Pin with Friction Ridges Lengthwise and Center Slots Black Part 2780 Element 4121715 or 278026 ×24
  • Technic Steering Arm with 2 Pins Black Part 32069 Element 6278276 or 4114671 ×2
  • Technic Wedge Belt Wheel Tire Black Part 2815 Element 6028041 or 281526 ×2
  • Technic Worm Gear Black Part 4716 Element 6037533 or 471626 ×4
  • Tread Large, Technic [34 Links] Black Part 71372 Element 4107488 ×2
  • Tyre 30 x 10.5 Offset Tread Black Part 2346 Element 234676 or 234626 ×4
  • Tyre 30.4 x 14 VR Black Part 6578 Element 4561806 or 657826 ×2
  • Tyre 43 x 17 Black Part 3634 Element 4523564 or 363426 ×4
  • Tyre 49.6 x 28 VR Black Part 6594 Element 75778 ×2
  • Tyre 81.6 x 15 Motorcycle Black Part 2902 Element 6226880 or 4562873 ×4
  • Tyre Offset Tread 24 x 8 Black Part 3483 Element 4501048 or 348326 ×2
  • Wire with Brick 2 x 2 x 2/3 Pair, 15L Black Part 5306bc015 Element 75565 ×6

Light Gray 315 pieces

  • Bracket 2 x 2 - 2 x 2 Light Gray Part 3956 Element 395602 ×4
  • Motor Pulley, 9V Micromotor with axle hole Light Gray Part 2983 Element 298630 ×4
  • Motor, 9V Mini [Old Style] Light Gray Part 71427c01 Element 4107786 ×1
  • Plate 1 x 1 Light Gray Part 3024 Element 302402 ×8
  • Plate 1 x 10 Light Gray Part 4477 Element 447702 ×6
  • Plate 1 x 2 Light Gray Part 3023 Element 302302 ×20
  • Plate 1 x 4 Light Gray Part 3710 Element 371002 ×10
  • Plate 1 x 6 Light Gray Part 3666 Element 366602 ×10
  • Plate 1 x 8 Light Gray Part 3460 Element 346002 ×8
  • Plate 2 x 10 Light Gray Part 3832 Element 383202 ×6
  • Plate 2 x 2 Light Gray Part 3022 Element 302202 ×8
  • Plate 2 x 2 Corner Light Gray Part 2420 Element 242052 or 242002 ×8
  • Plate 6 x 10 Light Gray Part 3033 Element 303302 ×1
  • Plate Special 1 x 2 with Door Rail Light Gray Part 32028 Element 4109642 ×8
  • Plate Special 2 x 2 with 2 Pin Holes Light Gray Part 2817 Element 281702 ×4
  • Sensor, Touch Light Gray Part 879 Element 4247135 or 4209116 ×2
  • Technic Axle 1.5 with Perpendicular Axle Connector (Technic Pole Reverser Handle) Light Gray Part 6553 Element 655302 ×4
  • Technic Axle 3 Light Gray Part 4519 Element 4186007 ×3
  • Technic Axle 5 Light Gray Part 32073 Element 4141482 ×2
  • Technic Axle Connector Ridged [with x Hole x Orientation] Light Gray Part 6538b Element 4113804 or 4100408 ×8
  • Technic Axle Connector with Axle Hole Light Gray Part 32039 Element 4106469 ×8
  • Technic Axle and Pin Connector Angled #5 - 112.5° Light Gray Part 32015 Element 4106378 ×4
  • Technic Axle and Pin Connector Perpendicular Light Gray Part 6536 Element 4173667 or 653602 ×6
  • Technic Axle and Pin Connector Perpendicular 3L with Pin Hole Light Gray Part 32068 Element 4114669 ×2
  • Technic Beam 1 x 3 Thin Light Gray Part 6632 Element 4107825 ×4
  • Technic Beam 1 x 4 Thin with Stud Connector Light Gray Part 2825 Element 4107133 or 282502 ×2
  • Technic Beam 1 x 5 Thin Light Gray Part 32017 Element 4106885 ×4
  • Technic Beam 3 x 3 L-Shape Thin Light Gray Part 32056 Element 4111941 ×4
  • Technic Bush Light Gray Part 3713 Element 4125313 or 659002 ×40
  • Technic Bush 1/2 Smooth with Axle Hole Reduced Light Gray Part 32123a ×18
  • Technic Cam Light Gray Part 6575 Element 657502 ×2
  • Technic Engine Crankshaft Center Light Gray Part 2854 Element 285402 ×2
  • Technic Gear 12 Tooth Bevel Light Gray Part 6589 Element 658902 ×8
  • Technic Gear 16 Tooth with Round Holes [Old Style] Light Gray Part 4019 Element 4107176 or 401902 ×4
  • Technic Gear 24 Tooth Crown with Reinforcements [New Style] Light Gray Part 3650c Element 365002 ×4
  • Technic Gear 24 Tooth [New Style with Single Axle Hole] Light Gray Part 3648b Element 4107543 or 364802 ×4
  • Technic Gear 40 Tooth Light Gray Part 3649 Element 364902 ×4
  • Technic Gear 8 Tooth Light Gray Part 3647 Element 364702 ×6
  • Technic Gear Rack 1 x 4 Light Gray Part 3743 Element 374302 ×4
  • Technic Gear Rack 1 x 8 with Holes Light Gray Part 6630 Element 663002 ×1
  • Technic Gear Timing Wheel 8 Tooth Light Gray Part 32060 Element 4141481 ×1
  • Technic Pin 1/2 without Friction Ridges Light Gray Part 4274 Element 427402 ×8
  • Technic Pin without Friction Ridges Lengthwise Light Gray Part 3673 Element 4184166 or 367302 ×24
  • Technic Plate 2 x 4 [3 Holes] Light Gray Part 3709 Element 370902 ×4
  • Technic Plate 2 x 6 [5 Holes] Light Gray Part 32001 Element 3200102 ×4
  • Technic Plate 2 x 8 [7 Holes] Light Gray Part 3738 Element 373802 ×8
  • Technic Steering Pulley Large Light Gray Part 3736 Element 373602 ×2
  • Technic Universal Joint 4L [Complete Assembly] Light Gray Part 9244 Element 9244 ×2
  • Technic Wedge Belt Wheel [aka Pulley] Light Gray Part 4185 Element 4100502 or 418502 ×4
  • Turntable 2 x 2 Plate - Top Light Gray Part 3679 Element 367952 or 367902 ×2

Yellow 51 pieces

  • Arm Grab Jaw Holder, 3 Fingers Yellow Part 4220 Element 4107528 or 422024 ×2
  • Brick 1 x 2 Yellow Part 3004 Element 4613966 or 300424 ×4
  • Brick Sloped 45° 2 x 1 with Bottom Pin Yellow Part 3040b Element 4121965 or 304024 ×4
  • Brick Sloped Inverted 45° 2 x 1 Yellow Part 3665 Element 366524 ×4
  • Cone 1 x 1 [No Top Groove] Yellow Part 4589 Element 458924 ×2
  • Hose Rigid 3mm D. 16L / 12.8cm Yellow Part 75c16 Element 4116948 ×2
  • Hub, RCX 2.0, No Power Jack [Complete Assembly] Yellow Part 884c ×1
  • Plate 1 x 3 Yellow Part 3623 Element 362324 ×2
  • Plate 2 x 4 Yellow Part 3020 Element 302024 ×6
  • Technic Beam 1 x 11.5 Double Bent Thick Yellow Part 32009 Element 6271150 or 6257104 ×4
  • Technic Brick 1 x 2 [1 Pin Hole] Yellow Part 3700 Element 370024 ×4
  • Technic Gearbox 2 x 4 x 3 1/3 Yellow Part 6588 Element 658824 ×1
  • Technic Pin Double with Axle Hole Yellow Part 32138 Element 4130596 or 4119438 ×2
  • Technic Rubber Belt Medium [26mm ID] [Round Cross Section] Yellow Part 85545 ×3
  • Wheel with Split Axle hole Yellow Part 3482 Element 348224 ×10

Blue 39 pieces

  • Plate 2 x 2 Blue Part 3022 Element 4613973 or 302223 ×4
  • Plate Round 1 x 1 with Solid Stud Blue Part 6141 Element 614123 ×2
  • Plate Round 2 x 2 with Axle Hole Type 1 (+ Opening) Blue Part 4032a Element 403223 ×2
  • Sensor, Light with Fixed Cable Blue Part 2982c01 Element 4119421 ×2
  • Technic Axle and Pin Connector Angled #1 Blue Part 32013 Element 6332570 or 4107797 ×4
  • Technic Axle and Pin Connector Angled #2 - 180° Blue Part 32034 Element 6484676 or 4107798 ×2
  • Technic Axle and Pin Connector Angled #6 - 90° Blue Part 32014 Element 4112205 ×4
  • Technic Axle and Pin Connector Perpendicular 3L with Centre Pin Hole Blue Part 32184 Element 4128599 ×2
  • Technic Beam 1 x 4 Thin Blue Part 32449 Element 6488701 or 4144283 ×2
  • Technic Beam 3 x 5 L-Shape with Quarter Ellipse Thin Blue Part 32250 Element 6371955 or 6339225 ×2
  • Technic Pin Long with Friction Ridges Lengthwise and Stop Bush [3 Lateral Holes, Big Pin Hole] Blue Part 32054 Element 4140800 or 4107741 ×4
  • Technic Rubber Belt Medium [24mm ID] [Round Cross Section] Blue Part 85544 ×3
  • Tile 1 x 2 with Groove Blue Part 3069b Element 306923 ×4
  • Turntable 2 x 2 Plate, Base Blue Part 3680 Element 368023 ×2

Green 31 pieces

  • Brick 1 x 2 Green Part 3004 Element 4107736 or 300428 ×4
  • Brick 2 x 4 Green Part 3001 Element 4106356 or 300128 ×1
  • Brick Curved 2 x 3 Green Part 6215 Element 621528 ×4
  • Brick Separator v1.0 Green Part 6007 Element 600728 ×1
  • Brick Sloped 45° 2 x 2 Green Part 3039 Element 303928 ×3
  • Plate 2 x 2 Green Part 3022 Element 302228 ×2
  • Plate 2 x 8 Green Part 3034 Element 303428 ×4
  • Technic Brick 1 x 2 with Axle Hole Type 2 [X Opening] Green Part 32064b ×8
  • Technic Brick 1 x 4 [3 Pin Holes] Green Part 3701 Element 4107790 ×2
  • Wedge Plate 3 x 6 Cut Corners Green Part 2419 Element 241928 ×2

White 25 pieces

  • Cone 1 x 1 [No Top Groove] White Part 4589 Element 458901 ×2
  • Dish 4 x 4 Inverted [Radar] White Part 3960 Element 396001 ×2
  • Light Brick 1 x 2 with Single Side Light White Part 6035 Element 4603220 or 74880 ×1
  • Plate Round 1 x 1 with Solid Stud White Part 6141 Element 6601919 or 614101 ×2
  • Plate Round 2 x 2 with Axle Hole Type 1 (+ Opening) White Part 4032a Element 6601914 or 403201 ×2
  • Rubber Belt Small [15mm ID] [Round Cross Section] White Part 85543 Element 6699001 or 4580665 ×3
  • Technic Gear 20 Tooth Double Bevel with Axle Hole Type 2 [X Opening] White Part 32269 Element 4205111 ×1
  • Technic Tread Hub White Part 32007 Element 4107487 ×4
  • Wheel 49.6 x 28 VR (36.8 x 26) with Axle Hole White Part 6595 Element 4496709 or 4179486 ×2
  • Wheel 61.6 x 13.6 Motorcycle White Part 2903 Element 290301 ×4
  • Wheel Rim 24 x 14 VR with Center Axle Hole White Part 2994 Element 4496671 or 299401 ×2

Dark Gray 22 pieces

  • Technic Axle 3 with Stud Dark Gray Part 6587 Element 4113884 or 658727 ×2
  • Technic Brick 1 x 2 [2 Pin Holes] Dark Gray Part 32000 Element 4157826 or 4101759 ×2
  • Technic Gear Differential, 24 -16 Tooth with Clutch on Both Sides Dark Gray Part 6573 Element 657327 ×1
  • Technic Pin 3/4 Dark Gray Part 32002 Element 4109854 ×16
  • Transmitter Tower, IR, USB Cable, with Black Front Dark Gray Part 23319c01 ×1

Tan 16 pieces

  • Technic Axle Pin without Friction Ridges Lengthwise Tan Part 3749 Element 4666579 or 4186017 ×16

Dark Turquoise 4 pieces

  • Hose, Ribbed 7mm D. 8L / 6.4cm Dark Turquoise Part 78c08 Element 4111953 ×4

Purple 4 pieces

  • Hose, Ribbed 7mm D. 11L / 8.8cm Purple Part 78c11 ×4

Trans-Dark Blue 4 pieces

  • Technic Modular Connector Trans-Dark Blue Part 32137 Element 4118978 ×4

Trans-Neon Orange 2 pieces

  • Creature Body Part, Dragon Wing Trans-Neon Orange Part 6133 Element 4106519 ×2

[No Color/Any Color] 2 pieces

  • Activity Booklet - Cover and Inventory Card - Set 9794 [No Color/Any Color] Part 9794bc ×1
  • Playmat / Test Mat for Mindstorms for Schools - Training Missions Activity Pad [No Color/Any Color] Part 45533 Element 4189432 ×1

Bright Green 1 piece

  • Storage Bin, Dacta, Medium Bright Green Part upn0038 ×1

Chrome Silver 1 piece

  • Dish 2 x 2 x 2/3 Light Reflector Chrome Silver Part 71128 Element 71128 ×1

Trans-Clear 1 piece

  • Storage Bin Lid, Dacta, 19 x 24 Trans-Clear Part 71082 ×1

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

When a piece really is missing

Ask LEGO

LEGO takes requests for pieces missing from a new set through its customer service site. The form asks for the set number and each piece's element ID, the number printed beside the piece in the parts list at the back of the instructions. This checker lists both.

Request a replacement from LEGO

Buy the piece

Mark a piece missing and your list links it to an eBay search for that part, which also covers pieces from older or second-hand sets.

Keep a record

Copy or download your missing list (the CSV opens in any spreadsheet), or print the whole checklist and tick pieces off on paper. Your marks stay in this browser, so you can check a big set over several sittings.