Butterfly Screw Clamp for 1 / 2" Tubing

This size is appropriate for the 1/2" hose.
This is a time-saving product. Forget about using screws and tools to tighten these clamps, all you need is your hands.
 
12 mm is the minimum opening and 20 mm is the maximum.
Width band:  9mm. 
(6221-1)