EXCELLENT MATERIAL: This architect key is made of high quality steel, the material is safe and hard, and the surface is bright nickel coating, which has good corrosion resistance and is durable. DESIGN CONCEPT : The tip of this universal structural wrench has a 3mm allen wrench and a short gear with a flat cam and 3 square wrenches on top. At the same time, it has a measuring scale, which is very convenient. PRODUCT PARAMETERS: 3 square keys, the size is 6, 7 and 8 mm. Used to check the heating valve or open the ventilation grille; the handy scale on the side measures cylinder length from 25-75mm. ALLEN KEY: There is a 3mm Allen key at the tip and a short gear with a flat cam. Used to loosen or fix door handles. The control cabinet and the maintenance cover can also be opened effortlessly. MULTIFUNCTIONALITY: The construction key is a ruler for measuring the angle of the contour cylinder. It can also be used as an ideal auxiliary tool for the control cabinet key or the door handle has not been installed, and it can also be used as a bottle opener. Product size: 19.5 mm Product colour: silver Scope of delivery: One piece