Application*** The radiator valve keys are mainly used on faucets and radiators, 5mm radiator keys can be used as drive wrenches for the same size.Keys are designed for the bleeding of domestic radiators - Has a square opening.great for replacing, avoiding the central heating system breaking down during the winter months.Suitable for many radiators on the market. Size *** The thickened radiator valve key has 5 x 5mm/0.2 x 0.2 inch square hole,The extended radiator valve key has 5 x 5mm/0.2 x 0.2 inch square holeTwo lengths to meet your different needs. Easy to Use & Portable*** Simply place the universal square key on the radiator valve (the air valve on the side of the radiator) and turn it carefully. For safety, place a water container underneath.Every radiator lock key feature 2 pre-drilled hole for convenient carrying and storage, not easy to get lost. Material*** The radiator keys are made of zinc alloy, not easy to break or rust, strong and durable, can serve for a long time. Package*** 8 PCS Radiator Keys(4Pcs thickened and 4Pcs extended) - The square radiator key is lightweight, sturdy and durable, you can use it for a long time. The solid opening key is a good tool to save your efforts, it's not easy to deform and break while use it many times. - Radiator key bleed key uk can serve as practical wrench, and turn the screws, suitable for many valves of electric, water, gas, train, cabinet, elevator, etc. Specification : Material: Zinc Alloy Color: Silver Quantity:8 Pieces Size : Thickened Radiator Key: 24.7 x 20mm/0.97 x 0.79 inches Extended Radiator Key: 24 x 26.2mm/0.94 x 1.03 inches * Warm notice: Radiator key bleed key uk is not suitable for some kind of radiator, notice the size of the key before you placing the order, don't order by mistake! Package includes: 4 * Thickened Radiator Keys 4 * Extended Radiator Keys