16-40 mm Metric Tube OD Taper Gauge
A 76 x 90 x 6 mm pocket gauge with a tapered slot running from 14 mm to 44 mm. Push the end of a pipe, tube, hose or dowel into the slot and read its outside diameter from the tick where its centre stops. Ticks are every 2 mm from 16 to 40 mm, with long ticks at 20, 30 and 40, and their positions are corrected for the 11.3° taper. It covers the in-between metric sizes that hardware-store clamps skip, so you can buy or print the right saddle. A 6 mm hole lets you hang it.
tool gauge pipe tube