The praxis works osbb converter for specialized has been designed to be a proper bottom bracket for shimano hollowtech cranks in specialized39s osbb frames praxis works patent pending design keeps the cartridge bearings outboard of the frame right on spec for a great rigidity and free of framec clip tolerance issues that other systems deal with all you simply need to do is press in the longer non drive cup then the shorter drive cup threads into it as the drive cup threads in praxis wor