ACB 6805 CC 1" Angular Contact Black Oxide treated Headset bearing (27.15mm x 38mm x 6.5mm: 36 x 45deg) -

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. All Enduro Black Oxide headset bearings carry a two-year warranty.

This size bearing is also known in the bike Industry by these part numbers:
HD 1320K
428420
TH-373
MR055
BAA1159
MH-P09K

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 lines, 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, decreasing friction, minimizing wear and maximizing life.

Static load - 788lbf / 3.50kN 
Weight - 17.67g