Cup wheel guards are used with large grinders only when using Type 11 flared cup wheels Type 11 5" flared cup wheel. Bosch Power Tools and Accessories is one of the divisions within the Robert Bosch Tool Corporation, which is one of the largest power tool and accessory manufacturers in the world. Bosch provides a complete line of corded and cordless power tools and accessories engineered to survive any jobsite and allow professionals to take control of their work.