BuildMyMTB
Prototype - Evolving Daily

Box Box Chain

Chain: Drivetrain system Box Prime 9 (9-speed); 9-speed (rear index count the maker rates it for). 2 verified variants, model year 2019.

What the checker says40will not fit

Run variant by variant through the mountain bike builder’s own engine. Every sentence below is the checker’s, unedited. Nothing here says this part fits your bike; it says what it does and does not fit among the parts we hold.

Checked against 6129 verified mountain bike parts in this catalog. 5915 produced no finding of any kind. Each variant produces 40 distinct errors and 0 distinct warnings.

Will not fit

  • Will not fiterror · Rear DerailleurDrivetrain mismatch: Derailleur = Shimano LinkGlide (CUES), Chain = Box Prime 9 (9-speed). Shifter, derailleur, cassette, chain and front derailleur must be one system. On 21 of the 75 verified rear derailleurs in this catalog. Applies to all 2 variants.
  • Will not fiterror · Rear DerailleurDrivetrain mismatch: Derailleur = Shimano 12-speed, Chain = Box Prime 9 (9-speed). Shifter, derailleur, cassette, chain and front derailleur must be one system. On 19 of the 75 verified rear derailleurs in this catalog. Applies to all 2 variants.
  • Will not fiterror · ShifterDrivetrain mismatch: Shifter = Shimano 12-speed, Chain = Box Prime 9 (9-speed). Shifter, derailleur, cassette, chain and front derailleur must be one system. On 19 of the 53 verified shifters in this catalog. Applies to all 2 variants.
  • Will not fiterror · CassetteDrivetrain mismatch: Cassette = Shimano LinkGlide (CUES), Chain = Box Prime 9 (9-speed). Shifter, derailleur, cassette, chain and front derailleur must be one system. On 16 of the 60 verified cassettes in this catalog. Applies to all 2 variants.
  • Will not fiterror · CassetteDrivetrain mismatch: Cassette = Shimano 12-speed, Chain = Box Prime 9 (9-speed). Shifter, derailleur, cassette, chain and front derailleur must be one system. On 15 of the 60 verified cassettes in this catalog. Applies to all 2 variants.
  • Will not fiterror · Rear DerailleurDrivetrain mismatch: Derailleur = SRAM Eagle 12-speed, Chain = Box Prime 9 (9-speed). Shifter, derailleur, cassette, chain and front derailleur must be one system. On 12 of the 75 verified rear derailleurs in this catalog. Applies to all 2 variants.
  • Will not fiterror · Front DerailleurDrivetrain mismatch: Chain = Box Prime 9 (9-speed), Front derailleur = Shimano LinkGlide (CUES). Shifter, derailleur, cassette, chain and front derailleur must be one system. On 12 of the 34 verified front derailleurs in this catalog. Applies to all 2 variants.
  • Will not fiterror · Front DerailleurDrivetrain mismatch: Chain = Box Prime 9 (9-speed), Front derailleur = shimano-8. Shifter, derailleur, cassette, chain and front derailleur must be one system. On 12 of the 34 verified front derailleurs in this catalog. Applies to all 2 variants.

Drivetrain system, Shifter. 11 more findings from the same check, on up to 11 of the 53 verified shifters each.

Drivetrain system, Rear Derailleur. 10 more findings from the same check, on up to 7 of the 75 verified rear derailleurs each.

Drivetrain system, Cassette. 9 more findings from the same check, on up to 9 of the 60 verified cassettes each.

Drivetrain system, Front Derailleur. 2 more findings from the same check, on up to 6 of the 34 verified front derailleurs each.

Open a variant in the builder to see the ones that apply to your own parts.

The checker compares the dimensions listed in what we check, and what we don’t. “No conflicts found” means no conflict among those dimensions — not a guarantee that a build works. Errors mean it won’t fit; warnings mean it works but check; infos are notes.

$22.99 to $34.99 MSRP·305 g

What the maker states

Speeds
9-speed (rear index count the maker rates it for)
System
Drivetrain system Box Prime 9 (9-speed)

2 verified variants

VariantPrice (MSRP)WeightSourceLast checkedBuild
Box Three Prime 9 126L (2019)$22.99305 gmaker’s page2026-07-14Build with this
Box Two Prime 9 126L$34.99not statedmaker’s page2026-07-31Build with this
The rest of what the maker states2 not published

2 further fields the checker looks for are not published by Box, so we leave them blank rather than estimate them, and those 2 checks stay silent on this chain. They are chain width and half link. Each is recorded as “not stated by the maker (not checked)”.

Source: each variant links the maker’s own page in the table above. Last checked 2026-07-14 to 2026-07-31.

Checked against

The checker ran this model against every verified part below that it has a slot for, the same way it checks a build in the builder. What follows is the verdict it actually produced for that specific pairing — not a recommendation, and not a guarantee any of these parts fits your own bike.

6 of 1874 counterparts with a page of their own that the checker actually probed this model against, in alphabetical order by brand and model — never by price, popularity or the verdict itself.

Where this sits

All Box chainsOpen a variant in the builder to see the ones that apply to your own parts