Quantity per package: you will receive 2 radiator keys, ideal for replacement and helping to maintain central heating systems during winter months Measurement: the radiator key measures approximately 3 x 2.2 cm (1.18 x 0.866 inches); the inner square edge is 5 mm (0.197 inches) and the outer diameter is 8 mm (0.315 inches). One size fits most radiators on the market, offering easy use and convenience Strong material: these radiator keys are made of quality zinc alloy, lightweight, practical, durable, and sturdy. They are resistant to breakage, easy to hold and turn, and show no deformation even after use on tight valves Utility design: lightweight and durable construction helps reduce effort when bleeding radiators. A practical and reliable tool for household use, designed to resist breakage and deformation Wide applications: suitable for bleeding air from radiators, this key is a helpful addition to home maintenance tasks