A worm drive hose clamp with a 9mm band and a 12mm to 20mm clamping range. It covers the step up from the smallest engine bay hoses into light coolant bypass work, heater take-offs, crankcase breather lines and short silicone joiners on 22mm to 25mm alloy pipework. The narrow band keeps the clamp compact, which helps when the joint sits close to a casting or bracket and a wider clamp would foul. Seat it squarely over the spigot barb and tighten gradually rather than in one pull. If your hose sits right at the top of the range, step up to the next size for a better margin.