This is mine. It's started life as a1/4in flexible head torque wrench. We then put a pass through 1/4in head on it, and then we put the guts of the 3/8in pass through into the 1/4in head, they are the same size BTW. We then reamed the pass through out to I believe a 5/16in hole so I can pass a 5mm Allen through it so that I can adjust the valves on the Cummins X-15 CNG Engines, and do the exhaust brake adjustments on the ISX 12N and G engines.