Durable Zinc Alloy Material: Made from solid zinc alloy with a 5mm internal square opening, this radiator bleed key provides strong resistance to bending and long-term reliability. Easy Clock-Key Operation: Designed with a clock-style grip, the key offers comfortable handling and effortless turning for smooth radiator bleeding. Universal Compatibility: The square opening fits most UK radiator valves, making it a practical tool for standard home heating systems. Helps Maintain System Efficiency: Regular use of the bleed key helps release trapped air, reduce system pressure, and support stable heating performance. Compact and Portable: Small, sturdy, and easy to store or carry, this 2-piece set ensures you always have a dependable radiator key available when needed., Manufacturer: Elenviorina