Discussion Starter · #1 ·
You don't need a specifically metric hose clamp. They run in a range and have a certain amount of adjustment. Your example 3cm is around 1 & 3/16 inch. Get a hose clamp that will cover that.the OD of the hose is probably metric, i.e., 3cm, may be hard to find a hose clamp for it in the hardware store.