WELDTITE Bagged 2 Caged Hardened Steel Ball Bearings Races Available in 2 options: 5/32 caged bearings for a traditional 1 inch headset (CAGE I.D 31mm - O.D 37mm) 3/16 caged bearings for a traditional BMX & old school MTB 1 inch headset (CAGE I.D 31mm - O.D 39.8mm) PLEASE REMEMBER WHEN FITTING CAGED BALL BEARINGS THE BEARINGS FACE INTO THE CUPS NOT THE CAGE.