Enduro bearing ACB 4545 1125 BO 1-1/8" 30.5x41.8x6.5mm

ACB 4545 1125 BO - 1-1/8" Black Oxide Angular Contact Headset bearing (30.5mm x 41.8mm x 6.5mm: 45x45 deg)

Angular-contact headset bearing featuring anti-corrosion Black oxide/Magnetite coated 52100 High-Carbon Chromium alloy races paired with grade 10 Balls. Black Oxide coating provides an extra level of corrosion resistance and extended worry-free performance

This size bearing is also known in the bike Industry by these part numbers:
MR042
870E
MR121
MR070
MR084
MR116
TH-870E
MH-P08

The Enduro line of angular-contact headset bearings start with Black Oxide treated Chromium Steel races, steps up to full 440C stainless steel, and the top of the line is, lifetime-guaranteed, XD-15 aerospace-stainless (races and balls). They are always engineered with the largest balls possible, feature dual-lip seals riding in a micro-groove (labyrinth) and are filled 90% with high pressure water proof grease for the ultimate protection against sweat and the elements. Enduro Angular Contact (A/C) bearings are designed so all balls are evenly engaged to spread the force over a larger surface area, minimizing wear and maximizing life

Static load - 980lbf / 4.35kN
Weight - 19.24g