Enduro HDK-0013 Drop-In Headset Kit - IS41/28.6 Upper | IS52/40 Lower, 36x45, Angular Contact Bearings, Tapered, BlackThis Enduro Integrated Drop In headset for 1 1 8" x 1 1 2" tapered fork steerer tubes features Angular Contact Bearings with chamfers, premium 440C balls and races, and 90% fill with high pressure waterproof grease. This top quality Drop In headset is built for long lasting durability thanks in part to the high performance bearings that are guaranteed for as long as you own the bike. This IS41 IS52 Integrated Drop In headset fits bikes with head tubes