Stainless steel discs absorb parallel, angular and unallocated shaft end slots with the same clockwise and counterclockwise rotation characteristics XBW Hubs manufactured from extra superhard aluminum (A7075) -- High strength aluminum alloy XBWS with full stainless steel construction are offered in a variety of sizes. Diameter: φ15 ~ φ104 diameter: φ3 ~ φ50 There are two different end hole diameter of the finished product inventory.