No more struggling bleeding radiators. It can be a challenge or even impossible to get a radiator to bleed. The bleed key just doesn't seem to fit the vent right, often its on old radiators but some rad vents can get a bit rounded and smaller on the new radiators too. Our key has the standard metric size and an imperial smaller sized bleed vent that fits all radiator vents you might come across, old & new. Additionally being made from a hard material like stainless steel and with the extra lever

Radiator (engine cooling) - Alchetron, the free social encyclopedia

How Radiator Works in Automobile? - Easiest Explanation - Mechanical Booster