AT500-MBBBRKBEARING REPLACEMENT KIT FOR ALIGN TREX 500 METAL BEARING BLOCK UPGRADE (AT500-MBB)Kit Includes:- Two (2) Radial Ball Bearings 8 x 16 x 5 mm- Two (2) Thrust Ball Bearings 8 x 15 x 5 mm- Two (2) Round Hole Shims 8.1 x 12 x 1 mm