This Rothenberger Universal 5-in-1 Stopcock Key is designed to open most crutch head valves and square stop taps. It features a multi-fit head with a tapered tommy bar for lifting access covers. It can be used to turn off stopcocks below ground level, fitting 1/2", 3/4", and 5/8" square stop taps, as well as 1/2" and 3/4" crutch head valves. Its robust design allows it to turn stiff stop taps, and the tapered flat end is ideal for lifting access covers.