A worm drive hose clamp with a 12mm wide band and a 20mm to 32mm clamping range. The wider band is the point of difference here: it spreads the load across more of the hose wall, which gives a more even seal on thicker coolant hose and on silicone couplers than a narrow 9mm band manages. That makes it a better choice for main coolant runs, radiator and header tank connections, and small silicone joins on alloy pipework. Position it fully over the spigot barb and tighten gradually. Confirm there is enough straight hose length for the wider band to sit flat and not overhang a curve.