BlockTalk Find Your Set

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.

Control Lab Building Set

Checking

9701 Control Lab Building Set

576 pieces in 122 part and color combinations.

LEGO counts 527 pieces. This inventory comes from a separate parts catalog and lists 576; 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

Plates 71 pieces

  • Plate 1 x 2 Black Part 3023 Element 302326 ×24
  • Plate 1 x 3 Black Part 3623 Element 362326 ×4
  • Plate 1 x 4 Black Part 3710 Element 371026 ×12
  • Plate 1 x 6 Black Part 3666 Element 366626 ×8
  • Plate 1 x 8 Black Part 3460 Element 346026 ×9
  • Plate 2 x 2 Black Part 3022 Element 302226 ×4
  • Plate 2 x 2 Corner Black Part 2420 Element 242026 ×6
  • Plate 2 x 3 Black Part 3021 Element 302126 ×2
  • Plate 4 x 4 Black Part 3031 Element 4243819 or 303126 ×2

Bricks 69 pieces

  • Brick 1 x 2 Black Part 3004 Element 300426 ×10
  • Brick 1 x 2 x 5 with Blocked Open Studs and Bottom Stud Holder with Asymmetric Ridges Blue Part 2454a Element 245423 ×2
  • Brick 1 x 6 Blue Part 3009 Element 300923 ×4
  • Brick 1 x 1 Red Part 3005 Element 300521 ×8
  • Brick 1 x 16 Red Part 2465 Element 6378410 or 246521 ×1
  • Brick 1 x 2 Red Part 3004 Element 4613961 or 300421 ×14
  • Brick 1 x 4 Red Part 3010 Element 301021 ×6
  • Brick 1 x 8 Red Part 3008 Element 300821 ×2
  • Brick 2 x 2 Corner Red Part 2357 Element 235771 or 235721 ×6
  • Brick 2 x 4 Red Part 3001 Element 300121 ×4
  • Brick 1 x 2 without Bottom Tube Trans-Dark Blue Part 3065 Element 6514264 or 6244906 ×1
  • Brick 1 x 2 without Bottom Tube Trans-Green Part 3065 Element 6514266 or 6244908 ×1
  • Brick 1 x 2 without Bottom Tube Trans-Red Part 3065 Element 6514263 or 6244905 ×1
  • Brick 1 x 2 without Bottom Tube Trans-Yellow Part 3065 Element 6514265 or 6244907 ×1
  • Brick 1 x 2 x 5 with Blocked Open Studs and Bottom Stud Holder with Asymmetric Ridges Yellow Part 2454a Element 245424 ×4
  • Brick 1 x 6 Yellow Part 3009 Element 300924 ×4

Technic Bricks 67 pieces

  • Technic Brick 1 x 10 [9 Pin Holes] Red Part 2730 Element 273021 ×8
  • Technic Brick 1 x 12 [11 Pin Holes] Red Part 3895 Element 389521 ×6
  • Technic Brick 1 x 16 [15 Pin Holes] Red Part 3703 Element 370321 ×6
  • Technic Brick 1 x 2 [1 Pin Hole] Red Part 3700 Element 370021 ×16
  • Technic Brick 1 x 4 [3 Pin Holes] Red Part 3701 Element 370121 ×10
  • Technic Brick 1 x 6 [5 Pin Holes] Red Part 3894 Element 389421 ×11
  • Technic Brick 1 x 8 [7 Pin Holes] Red Part 3702 Element 370221 ×10

Technic Special 60 pieces

  • Technic Link Tread Black Part 3873 Element 387326 3 spares in the box ×54
  • Technic Plate 1 x 5 with Toothed Ends, 2 Studs and Center Axle Hole Black Part 2711 Element 4279391 or 4195722 ×2
  • Technic Cable Holder White Part 70376 Element 70376 ×4

Tiles 47 pieces

  • Tile 1 x 2 with Groove Black Part 3069b Element 306926 ×4
  • Tile 1 x 4 with Groove Black Part 2431 Element 243126 ×4
  • Tile 1 x 8 with Groove Black Part 4162 Element 416226 ×8
  • Tile 1 x 2 with Groove Blue Part 3069b Element 306923 ×6
  • Tile 1 x 4 with Groove Blue Part 2431 Element 243123 ×4
  • Tile 1 x 2 with Groove Light Gray Part 3069b Element 306902 ×2
  • Tile 1 x 2 with Groove Red Part 3069b Element 4178178 or 306921 ×2
  • Tile 1 x 2 with Groove White Part 3069b Element 6548264 or 306901 ×2
  • Tile 2 x 2 with Black Wide Arrow Print White Part 3068bpr0050 Element 80607 ×1
  • Tile 2 x 2 with Groove White Part 3068b Element 6548263 or 306801 ×2
  • Tile 2 x 2 with Ice Cream Cone Print White Part 3068bpr0087 Element 81770 ×2
  • Tile 1 x 2 with Groove Yellow Part 3069b Element 306924 ×6
  • Tile 1 x 4 with Groove Yellow Part 2431 Element 243124 ×4

Technic Gears 37 pieces

  • Technic Gear 16 Tooth with Round Holes [Old Style] Light Gray Part 4019 Element 4107176 or 401902 2 spares in the box ×2
  • Technic Gear 24 Tooth Crown with Reinforcements [New Style] Light Gray Part 3650c Element 365002 ×4
  • Technic Gear 24 Tooth [Old Style - Three axle holes] Light Gray Part 3648a ×4
  • Technic Gear 8 Tooth Light Gray Part 3647 Element 364702 ×8
  • Technic Gear Rack 1 x 4 Light Gray Part 3743 Element 374302 ×14
  • Technic Turntable Large Type 1 Base, 56 Tooth Light Gray Part 2856 Element 285602 ×1
  • Technic Turntable Large Type 1 Top, 56 Tooth Light Gray Part 2855 Element 285502 ×1
  • Technic Worm Gear Light Gray Part 4716 Element 471602 ×3

Technic Bushes 30 pieces

  • Technic Bush Light Gray Part 3713 Element 4125313 or 659002 1 spare in the box ×16
  • Technic Bush 1/2 Toothed Type II [X Opening] Light Gray Part 4265b Element 4100501 or 657702 1 spare in the box ×14

Technic Pins 30 pieces

  • Technic Pin with Friction Ridges Lengthwise and Center Slots Black Part 2780 Element 4121715 or 278026 ×24
  • Technic Axle Pin without Friction Ridges Lengthwise Light Gray Part 3749 Element 4184168 or 4154179 2 spares in the box ×6

Wheels and Tyres 27 pieces

  • Technic Wedge Belt Wheel Tire Black Part 2815 Element 6028041 or 281526 ×4
  • Tyre 14 x 4 Smooth Small Single Black Part 3139 Element 313926 ×1
  • Tyre Offset Tread 24 x 8 Black Part 3483 Element 4501048 or 348326 ×8
  • Technic Wedge Belt Wheel [aka Pulley] Light Gray Part 4185 Element 4100502 or 418502 ×5
  • Wheel with Split Axle hole Light Gray Part 3482 Element 348202 ×4
  • Wheel Centre Small with Stub Axles (Pulley Wheel) Trans-Clear Part 3464 ×1
  • Wheel with Split Axle hole Yellow Part 3482 Element 348224 ×4

Technic Axles 24 pieces

  • Technic Axle 10 Black Part 3737 Element 373726 2 spares in the box ×2
  • Technic Axle 12 Black Part 3708 Element 370826 ×4
  • Technic Axle 3 Black Part 4519 Element 6238084 or 451926 2 spares in the box ×2
  • Technic Axle 4 Black Part 3705 Element 370526 ×4
  • Technic Axle 6 Black Part 3706 Element 370626 ×6
  • Technic Axle 8 Black Part 3707 Element 370726 ×6

Electronics 23 pieces

  • Sound Brick, Round, 9V 2 x 2 x 1 1/3 with Two Space Noises Black Part 4774c02 Element 75814 ×1
  • Wire with Brick 2 x 2 x 2/3 Pair, 15L Black Part 5306bc015 Element 75565 ×2
  • Wire with Brick 2 x 2 x 2/3 Pair, 162L Black Part 5306bc162 Element 75656 ×6
  • Wire with Brick 2 x 2 x 2/3 Pair, 36L Black Part 5306bc036 Element 75652 ×2
  • Sensor, Light with Fixed Cable Blue Part 2982c01 Element 4119421 ×1
  • Sensor, Rotation Blue Part 2977c01 Element 4119420 ×2
  • Motor, 9V 5 x 4 x 2 1/3, Dark Gray Bottom Light Gray Part 2838c01 Element 4494210 or 74569 ×3
  • Light Brick 1 x 2 with Single Side Light White Part 6035 Element 4603220 or 74880 ×4
  • Sensor, Temperature, Short Cable Yellow Part 2980c01 Element 4119423 ×1
  • Sensor, Touch, Fixed Cable Yellow Part 2974c01 Element 4119422 ×1

Plates Special 19 pieces

  • Plate Special 1 x 2 with 1 Stud without Groove (Jumper) Black Part 3794a ×4
  • Technic Plate 2 x 4 [3 Holes] Black Part 3709 Element 370926 ×7
  • Technic Plate 2 x 8 [7 Holes] Black Part 3738 Element 373826 ×6
  • Plate Special 2 x 2 with 2 Pin Holes Red Part 2817 Element 281721 ×2

Gear Parts 17 pieces

  • Storage Bin, Dacta, Small Red Part upn0032 ×2
  • Storage / Sorting Tray, Dacta, 13 Compartment for Dacta Small Bin Trans-Clear Part 167915 ×1
  • Storage / Sorting Tray, Dacta, 6 Compartment for Dacta Small Bin Trans-Clear Part 167916 ×1
  • Storage Bin Lid, Dacta, 19 x 24 Trans-Clear Part 71082 ×2
  • Activity Booklet 1 - Greenhouse - Set 9701 [No Color/Any Color] Part 9701b1 ×1
  • Activity Booklet 1 - Parts Tray Organizer Card - Set 9701 [No Color/Any Color] Part 9701bc1 ×1
  • Activity Booklet 2 - Parts Tray Organizer Card - Set 9701 [No Color/Any Color] Part 9701bc2 ×1
  • Activity Booklet 2 - Vending Machine - Set 9701 [No Color/Any Color] Part 9701b2 ×1
  • Activity Booklet 3 - Car Testing Station - Set 9701 [No Color/Any Color] Part 9701b3 ×1
  • Activity Booklet 4 - Joystick Controlled Wheelchair - Set 9701 [No Color/Any Color] Part 9701b4 ×1
  • Activity Booklet 5 - Scanner - Set 9701 [No Color/Any Color] Part 9701b5 ×1
  • Activity Booklet 6 - Conveyor Belt - Set 9701 [No Color/Any Color] Part 9701b6 ×1
  • Activity Booklet 7 - Robot Arm - Set 9701 [No Color/Any Color] Part 9701b7 ×1
  • Instruction Sheet, Set 9701 [No Color/Any Color] Part upn0105 ×1
  • Instruction Sheet, Set 9701 [No Color/Any Color] Part upn0116 ×1

Bricks Sloped 13 pieces

  • Brick Sloped 33° 2 x 4 Double Black Part 3299 Element 4529155 or 329926 ×1
  • Brick Sloped 33° 3 x 1 Red Part 4286 Element 428621 ×2
  • Brick Sloped 45° 2 x 1 with Bottom Pin Red Part 3040b Element 4121934 or 304021 ×6
  • Brick Sloped Inverted 34° 3 x 1 without Internal Stopper Red Part 4287a ×4

String, Bands and Reels 8 pieces

  • Rubber Band Medium (Square Cross Section) Thin Cut Black Part 70012 Element 70012 2 spares in the box ×2
  • Technic Rubber Belt Medium [24mm ID] [Round Cross Section] White Part 85544 Element 70713 ×2
  • Technic Rubber Belt Medium [26mm ID] [Round Cross Section] White Part 85545 Element 70714 4 spares in the box ×4

Bricks Special 6 pieces

  • Brick Special 1 x 1 with Headlight Black Part 4070 Element 407026 ×6

Plates Round Curved and Dishes 6 pieces

  • Plate Round 2 x 2 with Axle Hole Type 1 (+ Opening) Black Part 4032a Element 403226 ×4
  • Dish 2 x 2 x 2/3 Light Reflector Chrome Silver Part 71128 Element 71128 ×2

Technic Beams 5 pieces

  • Technic Beam 1 x 4 Thin with Stud Connector Black Part 2825 Element 6331570 or 4107136 ×5

Panels 4 pieces

  • Panel 6 x 6 x 9 Corner Convex with Curved Top Trans-Clear Part 6002 Element 6343724 or 6225039 ×2
  • Panel 6 x 6 x 9 Curved Top Trans-Clear Part 2572 Element 6201906 or 4522224 ×2

Tiles Round and Curved 4 pieces

  • Tile Round 2 x 2 with Bottom Cross White Part 4150 Element 415051 or 415001 ×4

Baseplates 2 pieces

  • Baseplate 16 x 32 Light Gray Part 3857 Element 4219612 or 274802 ×2

Hinges, Arms and Turntables 2 pieces

  • Turntable 2 x 2 Plate, Base Black Part 3680 Element 368076 or 368026 ×1
  • Turntable 2 x 2 Plate - Top Light Gray Part 3679 Element 367952 or 367902 ×1

Technic Connectors 2 pieces

  • Technic Axle Connector Ridged [with + Hole + Orientation] Light Gray Part 6538a 2 spares in the box ×2

Transportation - Sea and Air 2 pieces

  • Propeller 2 Blade 9 Diameter Light Gray Part 2952 Element 4107163 ×2

Transportation - Land 1 piece

  • Wheel Holder 2 x 2 Thin with Clips, Plane Single Light Gray Part 2415 Element 241502 ×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.

We value your privacy

We use cookies 🍪 for analytics and to improve your experience. Read our privacy policy