Bosch rotary hammer, GBH 2-26 DRE, is a power tool that can perform heavy-duty tasks such as drilling and chiseling hard materials. It is similar to a hammer drill in that it also pounds the drill bit in and out while it is spinning. Compared to less advanced power units known as hammer drills, rotary hammers tend to be larger and provide a bigger impact force by utilizing a technology. The flying piston is at the other end of the same cylinder.