This is used to remove the bearing holders for the circa 90's Avid Arch Supreme linear pull brakes. I think at the time you could just buy full replacements (along with the tool), but now both are impossible to find. With this tool the brake arms can be completely disassembled and the bearings can be more easily removed and replaced.Print and press some bits of wire clothes hanger into the holes. To remove the bearings, the center insert needs to be pushed to the side (which can be difficult) and the bearings tapped out with something like a drift punch. The bearings can't be pushed all the way through because the center is narrower.