The Praxis M30 thru bottom bracket is designed to be a proper bottom bracket (BB) for installing the Praxis Lyft Carbon Crank. It will also work with RACE FACE CINCH or Rotor REX MTB cranks into 73mm BB30/PF30 mountain frames. The Praxis patent pending design keeps the Enduro 6806 cartridge bearings outboard of the frame for greater rigidity and free of frame/c-clip tolerance issues that other systems deal with. Simply press in the longer non-drive-cup, then thread the shorter Drive cup into it. As the drive cup threads in, the trademark Collet system expands to a precise limit evenly dispersing pressure for a super tight fit. With both cups connected and the collet set exactly to spec, there is no chance the bearings can come out of alignment or wiggle/walk out of the frame. This design also uses a compressible o-ring on the non-drive side cup to compensate for frame shell width discrepancies.