1/2 inch US drip tubing (1/2" US (0.700" OD))

Used on: US mainline drip tubing feeding 1/4 inch branches; the common half-inch size in the US.

US 1/2 inch drip tubing is nominally 0.700 inch outside but brands vary between 0.620, 0.700 and 0.710 inch, so a.700 fitting can be loose on.620 tubing. It is not the same as 16 mm metric pipe, and mixing the two is the classic drip leak.

Quick-connect click fittings from Hozelock, Gardena and Karcher are proprietary and do not interchange. They all sit on top of a standard thread underneath, so the reliable way to move between brands is to adapt at the threaded tap or hose-end fitting, then use each brand's own connector above it.