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.
Weapon Blade with Bar and 3 SpikesPearl TitaniumPart 19179Element 6103924×2
Dark Purple
2 pieces
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper)Dark PurplePart 15573Element 6092604×2
Trans-Red
2 pieces
Plate Round 1 x 1 with Solid StudTrans-RedPart 6141Element 6514051 or 6208450×2
Dark Brown
1 piece
Technic Axle and Pin Connector Angled Triple [120° Offset]Dark BrownPart 10288Element 6273219 or 6005755×1
Dark Tan
1 piece
Technic Axle 5 with StopDark TanPart 15462Element 6055631×1
Orange
1 piece
Brick and Axle Separator v2.0OrangePart 96874Element 6240515 or 4654448×1
Trans-Green
1 piece
Tile 1 x 1 with Dark Bluish Gray Square with Black Center and Lines Print (Ultra Chip)Trans-GreenPart 3070bpr0001Element 6254420 or 6083816×1
[No Color/Any Color]
1 piece
Sticker Sheet for Set 70170-1[No Color/Any Color]Part 20382Element 6105634×1
Minifigures
4 figures
Agent Caila Phoenix with Dark Azure HairMinifigure, checked as a whole figure×1
AntiMatterMinifigure, checked as a whole figure×1
Agent Max Burns with Helmet and Shoulder ArmorMinifigure, checked as a whole figure×1
Agent Solomon BlazeMinifigure, 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.
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.