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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.

Checking

79103 Turtle Lair Attack

466 pieces in 187 part and color combinations, plus 6 minifigures.

The official piece count includes the 22 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.

Every bag and the box. Shake out each bag, check its corners and seams, and look inside the empty box.
Inside what you have built. Small pieces lodge inside tubes, under plates and between studs. Turn the model over and look.
The last few steps. Compare each recent step with its parts callout. A piece used in the wrong place earlier leaves you one short later.
Look-alike colors. 1 part in this set come in two colors that are easy to mix up; they are listed below.
The spare pieces. This set comes with 32 spare pieces, marked on each row of the checklist. One may be the piece you need.
The floor and your building area. Check under furniture, the chair and the edges of your building surface.

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.

Plate 1 x 8 Black ×2 Dark Bluish Gray ×2 Black is darker than Dark Bluish Gray.

Piece checklist

Bricks Round and Cones 46 pieces

Cone 1 x 1 [Top Groove] Black Part 59900 Element 4529236 ×2
Brick Round 1 x 1 Open Stud Blue Part 3062b Element 306223 ×1
Brick Round 2 x 2 with Axle Hole Dark Bluish Gray Part 3941 Element 4249139 ×15
Brick Round 1 x 1 Open Stud Light Bluish Gray Part 3062b Element 4211412 ×14
Brick Round 1 x 1 Open Stud Red Part 3062b Element 306221 ×3
Brick Round 1 x 1 Open Stud Reddish Brown Part 3062b Element 4211183 ×4
Brick Round 2 x 2 with Axle Hole Reddish Brown Part 3941 Element 4211166 ×4
Brick Round 1 x 1 Open Stud Trans-Neon Green Part 3062b Element 6514237 or 6238675 ×2
Brick Round 1 x 1 Open Stud Yellow Part 3062b Element 306844 or 306224 ×1

Bricks Sloped 28 pieces

Brick Sloped 45° 2 x 1 with 2/3 Cutout [Original Version] Black Part 92946 ×2
Brick Sloped 45° 3 x 4 Double / 33° Dark Bluish Gray Part 4861 Element 6013539 or 4210905 ×1
Brick Sloped 65° 2 x 2 x 2 with Bottom Tube Dark Orange Part 3678b Element 4656509 ×2
Brick Sloped 65° 2 x 1 x 2 Light Bluish Gray Part 60481 Element 4515374 ×2
Brick Sloped 30° 1 x 1 x 2/3 (Cheese Slope) Olive Green Part 54200 Element 6002841 3 spares in the box ×12
Brick Sloped 45° 2 x 2 Olive Green Part 3039 Element 6016474 ×4
Brick Sloped 18° 2 x 1 x 2/3 with 4 Slots / Grate Red Part 61409 Element 4540382 or 4535102 ×4
Brick Sloped 45° 2 x 2 with Green Radar, Green/Red Buttons and Disk Slot Print White Part 3039pr0002 Element 4195659 ×1

Bricks 20 pieces

Brick 1 x 2 x 2 with Inside Stud Holder Dark Bluish Gray Part 3245c Element 4210978 ×2
Brick 1 x 3 Dark Bluish Gray Part 3622 Element 4211104 ×6
Brick 2 x 2 Light Bluish Gray Part 3003 Element 4211387 ×3
Brick 2 x 4 Light Bluish Gray Part 3001 Element 4211385 ×2
Brick 1 x 2 Red Part 3004 Element 4613961 or 300421 ×1
Brick 1 x 4 Reddish Brown Part 3010 Element 4211225 ×2
Brick 2 x 2 Reddish Brown Part 3003 Element 4211210 ×2
Brick 2 x 3 Reddish Brown Part 3002 Element 4216668 ×1
Brick 1 x 3 Tan Part 3622 Element 4162465 or 4113920 ×1

Bricks Curved 19 pieces

Brick Arch 1 x 6 x 2 - Very Thin Top without Reinforced Underside Dark Bluish Gray Part 12939 Element 6040252 ×3
Brick Arch 1 x 8 x 2 Dark Bluish Gray Part 3308 Element 4541748 or 4220973 ×1
Brick Arch 1 x 4 Dark Brown Part 3659 Element 4623775 ×2
Brick Arch 1 x 4 x 2 Light Bluish Gray Part 6182 Element 6031056 or 4225119 ×8
Brick Arch 1 x 5 x 4 [Irregular Bow, Raised Underside Cross Supports] Reddish Brown Part 76768 Element 6012805 ×2
Brick Curved 1 x 5 x 4 Inverted Tan Part 30099 Element 6560585 or 6334382 ×3

Tiles 12 pieces

Tile 1 x 1 with Groove Dark Bluish Gray Part 3070b Element 4210848 1 spare in the box ×1
Tile 1 x 3 Dark Bluish Gray Part 63864 Element 4568734 ×1
Tile 1 x 6 with Groove Dark Bluish Gray Part 6636 Element 4210651 ×3
Tile 1 x 2 with Groove Light Bluish Gray Part 3069b Element 4211414 ×3
Tile 1 x 4 with Groove Reddish Brown Part 2431 Element 4211194 ×4

Hinges, Arms and Turntables 10 pieces

Hinge Cylinder 1 x 2 Locking with 2 Click Fingers and Axle Hole, 9 Teeth Black Part 30553 Element 4143372 ×1
Hinge Cylinder 1 x 3 Locking with 1 Finger and Technic Friction Pin with Round Hole Black Part 41532 Element 4159335 ×1
Hinge Plate 1 x 2 Locking with 1 Finger On Top Black Part 30383 Element 6338799 or 4144575 ×1
Turntable 4 x 4 Square Base, Locking Black Part 61485 Element 4517986 ×1
Plate Special 4 x 6 with Trap Door Hinge [Long Pins] Dark Bluish Gray Part 92099 Element 4595710 ×1
Plate Special 6 x 8 Trap Door Frame Horizontal [Long Pin Holders] Dark Bluish Gray Part 92107 Element 4595708 ×1
Hinge Cylinder 1 x 3 Locking with 1 Finger and 2 Fingers On Ends, with Hole, 9 Teeth Light Bluish Gray Part 30554b Element 4550251 or 4211663 ×3
Hinge 1 x 2 Locking with 2 Fingers and Towball Socket, 9 Teeth Yellow Part 30396 Element 6146964 or 4163290 ×1

Minifig Shields, Weapons, & Tools 10 pieces

Tool Hammer / Mallet Large Black Part 4522 Element 452226 ×1
Tool Screwdriver and Spanner / Wrench Black Part 4006 Element 6034000 or 4569095 ×1
Weapon Sword / Katana / Shamshir with Uncapped Pommel [Square Guard] Black Part 30173b 1 spare in the box ×2
Weapon Sai Flat Silver Part 98139 Element 6270136 or 4646867 1 spare in the box ×2
Weapon Sword / Katana / Shamshir with Uncapped Pommel [Square Guard] Flat Silver Part 30173b Element 4569471 2 spares in the box ×3
Weapon Throwing Star / Shuriken with Smooth Grips Pearl Gold Part 93058 Element 4600519 1 spare in the box ×1

Supports, Girders and Cranes 9 pieces

Support Round 1 x 1 x 6 Solid Pillar Dark Bluish Gray Part 43888 Element 4180811 ×4
Support Round 1 x 1 x 6 Solid Pillar Dark Orange Part 43888 Element 6345561 or 6030306 ×4
Hook with Towball Dark Red Part 30395 Element 6008602 ×1

Tiles Special 8 pieces

Tile Special 1 x 1 with Clip with Rounded Tips Dark Bluish Gray Part 12825 Element 6030710 ×3
Tile Special 2 x 2 with Top Pin Dark Bluish Gray Part 2460 Element 4211129 ×1
Tile Special 1 x 2 Grille with Bottom Groove Light Bluish Gray Part 2412b Element 4211350 ×2
Tile Special 1 x 2 Grille with Bottom Groove Trans-Neon Green Part 2412b Element 4272661 or 4109766 ×2

Minifig Accessories 7 pieces

Tap 1 x 1 without Hole in Spout Black Part 4599b Element 459926 1 spare in the box ×1
Sports Skateboard with Trolley Wheel Holders Blue Part 42511 Element 4569105 or 4172695 ×1
Tap 1 x 1 without Hole in Spout Blue Part 4599b Element 459923 1 spare in the box ×1
Equipment Dynamite Sticks Red Part 64728 Element 6270088 or 4538780 ×1
Sports Skateboard with Trolley Wheel Holders Red Part 42511 Element 6030305 ×1
Tap 1 x 1 without Hole in Spout Red Part 4599b Element 459921 1 spare in the box ×1
Tap 1 x 1 without Hole in Spout Yellow Part 4599b Element 4256320 1 spare in the box ×1

Technic Pins 7 pieces

Technic Pin with Friction Ridges Lengthwise and Towball Black Part 6628 Element 4184169 or 662826 ×1
Technic Pin Long with Friction Ridges Lengthwise, 2 Center Slots Blue Part 6558 Element 4514553 ×2
Technic Pin 1/2 without Friction Ridges Light Bluish Gray Part 4274 Element 4274194 or 4211483 1 spare in the box ×2
Technic Pin without Friction Ridges Lengthwise Light Bluish Gray Part 3673 Element 4211807 or 3673194 1 spare in the box ×2

Tiles Round and Curved 7 pieces

Tile Round 1 x 1 Flat Silver Part 98138 Element 6238890 or 4655241 1 spare in the box ×2
Tile Round 1 x 1 with Gauge and Red Pointer Print Flat Silver Part 98138pr0012 Element 6287877 or 6030333 1 spare in the box ×1
Tile Round 2 x 2 with Bottom Cross Light Bluish Gray Part 4150 Element 4211480 ×1
Tile Round 2 x 2 with Bottom Cross Pearl Gold Part 4150 Element 4579099 ×2
Tile Round 2 x 2 with Pizza Print Yellow Part 4150pr0015 Element 81867 ×1

Panels 6 pieces

Panel 1 x 6 x 5 Dark Bluish Gray Part 59349 Element 4505068 ×4
Panel 1 x 2 x 1 [Rounded Corners] Green Part 4865b Element 6146227 or 4542189 ×1
Panel 1 x 2 x 1 with Rounded Corners and Central Divider Yellow Part 93095 Element 4621603 ×1

Technic Axles 6 pieces

Technic Axle 4 with Stop Dark Bluish Gray Part 87083 Element 6083620 or 4560177 ×2
Technic Axle 5.5 with Stop [Rounded Short End] Dark Bluish Gray Part 59426 Element 4508553 ×1
Technic Axle 3 with Stud Dark Tan Part 6587 Element 6031821 or 6013821 ×1
Technic Axle 7 Light Bluish Gray Part 44294 Element 44294194 or 4211805 ×1
Technic Axle 2 Notched Red Part 32062 Element 4142865 ×1

Technic Bricks 6 pieces

Technic Brick 1 x 14 [13 Pin Holes] Dark Bluish Gray Part 32018 Element 4211137 ×1
Technic Brick 1 x 2 [1 Pin Hole] Dark Bluish Gray Part 3700 Element 4211111 ×5

Wheels and Tyres 6 pieces

Wheel Skateboard / Trolley Black Part 2496 Element 6223673 or 4569104 ×4
Wheel 11 x 8 with Center Groove Light Bluish Gray Part 42610 Element 4211758 ×2

Plates Wedged 5 pieces

Wedge Plate 6 x 3 Left Dark Bluish Gray Part 54384 Element 4290149 ×2
Wedge Plate 6 x 3 Right Dark Bluish Gray Part 54383 Element 4290150 ×2
Wedge Plate 8 x 8 Cut Corner Dark Bluish Gray Part 30504 Element 4547222 or 4210956 ×1

Technic Connectors 5 pieces

Technic Pin Connector Round with 4 Clips Black Part 90202 Element 6320293 or 6052369 ×1
Technic Pin Connector Round [Slotted] Light Bluish Gray Part 62462 Element 6173127 or 4526985 ×3
Technic Axle Connector Smooth [with x Hole + Orientation] Red Part 59443 Element 4513174 ×1

Windows and Doors 4 pieces

Window 1 x 2 x 2 Castle Tan Part 90195 Element 4642933 or 4622128 ×4

Containers 3 pieces

Cupboard 2 x 3 x 2 with Hollow Studs Red Part 92410 Element 4619543 ×1
Cupboard 2 x 3 Drawer White Part 4536 Element 4520636 or 4109736 ×2

Technic Gears 3 pieces

Technic Gear 12 Tooth Double Bevel Black Part 32270 Element 4177431 ×1
Technic Gear 12 Tooth Bevel Tan Part 6589 Element 4565452 or 4514556 1 spare in the box ×2

Minifig Upper Body 2 pieces

Arm Mechanical with 2 Clips [Battle Droid] Black Part 30377 Element 6330086 or 4223247 1 spare in the box ×2

Plants & Trees 2 pieces

Plant, Leaves 6 x 5 Bright Green Part 2417 Element 6266964 or 4129872 ×2

Technic Beams 2 pieces

Technic Beam 2 x 4 L-Shape Thick Black Part 32140 Element 6271825 or 4120017 ×1
Technic Beam 1 x 3 Thick Red Part 32523 Element 4153718 ×1

Transportation - Land 2 pieces

Steering Wheel Small, 2 x 2 Light Bluish Gray Part 30663 Element 30663194 or 4211701 ×2

Animal / Creature Body Parts 1 piece

Animal Body Part, Barb / Claw / Tooth / Talon / Horn, Small Flat Silver Part 53451 Element 6270108 or 4612901 1 spare in the box ×1

Minifig Heads 1 piece

Minifig Head [Plain] [Hollow Stud] Trans-Clear Part 3626c Element 6001655 ×1

Stickers 1 piece

Sticker Sheet for Set 79103-1 [No Color/Any Color] Part 13056 Element 6023184 ×1

Technic Beams Special 1 piece

Technic Beam 3 x 0.5 Liftarm with Boss and Pin / Crank Black Part 33299a Element 4156980 ×1

Technic Bushes 1 piece

Technic Bush Red Part 3713 Element 6271820 or 4227155 1 spare in the box ×1

Technic Special 1 piece

Gearbox 4 x 4 x 1 2/3 with 1 x 2 Cutouts, Pin Holes Black Part 6585 Element 6169982 or 4500902 ×1

Technic Steering, Suspension and Engine 1 piece

Technic Steering Wheel Small (3 Studs Diameter) Light Bluish Gray Part 2819 Element 4580510 or 4211578 ×1

Tools 1 piece

Brick and Axle Separator v2.0 Orange Part 96874 Element 6240515 or 4654448 ×1

Minifigures 6 figures

Foot Soldier Minifigure, checked as a whole figure ×1
Warrior Statue Minifigure, checked as a whole figure ×1
Splinter Minifigure, checked as a whole figure ×1
Raphael Looking Up Minifigure, checked as a whole figure ×1
Leonardo Looking Up Minifigure, checked as a whole figure ×1
Dark Ninja Minifigure, checked as a whole figure ×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.