White Industries external BSA style bottom brackets are made here in our shop and feature Enduro stainless steel angular contact bearings or optional Enduro XD-15 ceramic-hybrid radial bearings. We offer them with three different bearing sizes to help you fit your favorite crank to your favorite bike. "BSA" bottom bracket shells and cups are named after the Birmingham Small Arms Company which created the thread standard used in this system. It's also referred to as "British" or "English" style and is the most common type of system found on modern bicycles. The "external" designation refers to the fact that the bearings will sit outboard of your frame's bottom bracket shell as opposed to being tucked inside the shell as you would find on some styles of BSA bottom brackets.