Allows you to use a standard BSA (GXP or otherwise) BB in a PF30 frame
Includes wave washer and shims for a perfect fit
Bottom Bracket standards have become incredibly confusing. The SramTruvativ GXP30 Bottom Bracket adapter doesn't make it any less confusing (let's be honest) but it does solve the problem of running GXP cranks with a PF30 frame.
In fact, the PF30-BSA adapter allows you to install any standard external bearing BB (excluding all things Campy) into a PF30 frame. This Sram adapter works by allowing you to thread your BSA BB into the adapter, then simply press the adapter cups into the frame and viola, GXP cranks on a PF30 frame.