High-end mid sized bb kit. The spacer will increase the longevity of the bearings as well as help with crank flips if thats your thing, so yeah, don't leave it out...
Alloy cnc cones, sealed bearing
For mid-bb frames, available for 19mm or 22mm spindle
High quality sealed bearings
Includes cones & spacers to adjust chainlines on 68mm to 73mm bb shells