This is the Chris King BSA ThreadFit 30mm bottom bracket, a threaded unit for 30mm-spindle cranksets in 68 or 73mm English-threaded shells. The steel bearings are made in-house in Portland, and a grease-injection system lets the bearings be purged and refreshed at home.
It ends the creak cycle that plagues press-fit and budget threaded bottom brackets under powerful riders, spinning quietly through winters that destroy lesser bearings. A conversion kit (sold separately) may be required for some crank designs.
Chris King Precision Components has machined bicycle components in Portland, Oregon since 1976, making its own bearings from domestic-mill materials and anodizing parts in-house.
