TKO Turning Knob Operator Turns knobs, faucets, valves and keys Turning device for people with hand disabilities or arthritis. Can be used in a work or home environment on any non-round control knob or appliance handle. When the turner is pressed onto a knob the pins contacting with the knobs surface retract, while the remaining pins surround the knob for a secure grip. Measures 2 1/4 (5.7 cm) in diameter but can grip larger irregular-shaped knobs. The T-shaped handle, 5 1/4 (13.3 cm) long, is ergonomically designed for ease of operation.