Apex Pipe-Plug screwdriver bits. Male hex, to male square from 1/4'' to 1/2''. These Apex pipe plug screwdriver bits can be used for driving screws and fasteners with hand tools, corded or cordless power tools, and pneumatic tools. Apex Bits offers a number of male square insert screwdriver bits for pipe plugs, which are commonly used with Apex Bit Holders. Commonly used in aircraft assembly, maintenance and throughout the aviation industry. Apex quality begins with select raw materials. Only carefully chosen, high grade tool steel is used.