Brake Cylinder Hone 2 Blade 220 Grit 1/2" to 2 1/4" (12.7mm to 57mm) Works in bore of 1/2" (12.7mm) to 2 1/4" (57mm) Controlled pressure for faster, smoother, consistent honing action Flexible Shaft, Adjustable collar for increasing pressure Two 220 grit aluminum oxide grinding stones grinding stone dimensions: 1-1/8" L x 2-9/16" W x 3/4" diameter