OTC Tools is an affiliated Bosch Tools brand and major supplier for servicing tools and equipment. They offer these various size cylinder hones for any resurfacing and resizing jobs. Bores, brake calipers, engine lifters, U-joints, yokes, bearing or bushings are a great option to be used on. Equipped with 180 grit silicone carbide, provides excellent cutting and finished surfaces. OTC manufactures all parts for long lasting durability.