The thing to sort out before buying any SRAM DUB bottom bracket is which shell your frame has, because DUB isn't a bottom bracket standard — it's SRAM's 28.99mm spindle system that runs across every shell type. The bottom bracket itself still has to match your frame. SRAM offers this MTB DUB bottom bracket in three shells covered here: BSA 73 threaded with a 55mm Boost chainline, PF30 73 pressfit, and PressFit 89.5/92 (also called BB92). Pick the one that matches your frame and you're set to run any SRAM DUB crankset.

The DUB spindle sits at 28.99mm — about 1mm smaller than the 30mm standard, but larger than the 24mm GXP spindle SRAM used to run. That in-between diameter is the whole point. It lets SRAM build one crankset spindle that fits into every shell standard on the market, so you're not stuck matching a 24mm GXP crank to a BSA frame and a separate 30mm crank to a PressFit frame. If you're upgrading from GXP to a newer SRAM crankset — GX Eagle, X0 Eagle Transmission, XX SL, whatever — you'll need a DUB bottom bracket to go with it.

Gutter Seal Technology handles the sealing, which is the part that matters on a mountain bike. The seal design improves protection against the elements, and the sealed cartridge bearings run in aluminum cups on the BSA and PF30 versions. The BB92 pressfit version uses steel cups instead of aluminum, which is the trade-off SRAM made to get the durability up on the smaller PressFit 92 shell. All three versions use the same DUB spindle interface, so any DUB crankset drops into any of them once the shell matches your frame.