Abstract: A tool unit including a handheld power tool and a side handle mechanically connected to the power tool, wherein the side handle has a threaded rod. The power tool has an undercut groove delimited by a groove bottom, and the side handle has a channel nut engaging the undercut groove, wherein the channel nut has a threaded hole, wherein the threaded rod of the side handle is threadedly engaged in the threaded hole of the channel nut and acts against the groove bottom of the undercut groove. Side handles and power tools for use in such a tool unit are also provided.