Wheels Manufacturing Outboard BB Shell for MTB with Shimano Compatible for AC Bearings, Red Standard Radial bearings. USA Machined aluminum cups for superior durability Will accept current 22-24mm (SRAM, Truvativ GXP) cranks Enduro ABEC 3 sealed bearings. Dual silicone seal keeps the contamination out for longer life. Serviceable bearings Made in the USA