FSA Headset Bearing 1 1/8 36x45 11/8 - 41OD x 30.2ID x 6.5H - 873E

Commonly found 1 1/8" headset bearings, with some models available in different material options. SL Light bearings have an alloy outer race to reduce weight, although expect more frequent replacement intervals than with chrome steel or stainless bearings.