A power tool adaptor for holding a tool adapted thereto including an adaptor body, a tool insertion cavity formed in an end of the adaptor body for receiving the tool, an elongated tool bit insertion cavity formed as a continuation of the tool insertion cavity, means for fixating the tool by protruding into one or more fixation recesses on the outer surface of the tool and means for attaching the power tool adaptor to a power tool; a reversible tool bit holder is further disclosed for holding two changeable tool bits, which reversible tool bit holder is adapted to fit into the power tool adaptor, along with a kit including a power tool adaptor and a reversible tool bit holder adapted to fit into the power tool adaptor.