I purchased 1/4" ID and 3/8" OD tubing. Once I put the tubing over the barbs, my 3/8" clamps that I had, would not fit. Bought this and it worked out perfect. I replaced all of the lines in my kegerator.

Great clamps with a tight seal

Perfect for beer supply lines from a Sankey connector.

It's printed 12.8mm, which technically covers 7/16"OD range, but when you put it on a hose barb it isn't big enough to handle hose expansion. I got some PEX 13.3mm clamps (3/8"), and those aren't big enough either. PEX 17.5mm clamps (1/2") are too big. So ... I'm still on the hunt for around 15mm clamps. These 7/16" stepless hose clamps are fine manufacturing; they just don't fit my needs.

Close easily, smotohly and without leaving gaps from uneven compression

It’s a clamp what can I say

These are far superior to the screw clamps. Much neater and less likely to leak. On the downside, they are not re-usable and fit only one size of hose, so you will likely need more than one size.

Exactly what I needed for my beer lines in my homemade kegerater.