A worm drive hose clamp with a 9mm band covering a 16mm to 25mm clamping range. This is a genuinely versatile size in a build, handling heater hoses, coolant bypass runs, larger breather plumbing and the silicone couplers used on small alloy pipework. The generous range means one clamp size covers several hose diameters, which is useful when you are fabricating and the final sizes are not yet settled. Fit the clamp over the barb, keep the band square to the hose and tighten steadily. Re-check the tension after the first heat cycle, as silicone and rubber both settle once they have been up to temperature.