The Knipex Profi-Key is suitable for all standard shut-off systems in the supply of gas, water and electricity for technical installations in buildings, e. g. heating, air conditioning and ventilation systems, shut-off valves,mains switch-boards, etc. Supplied with a securing chain. It has the following functions: 3 x Square: 5, 7 & 8mm.1 x Triangular: 9-10mm. 1 x Two-Way: 3-5mm.1 x Long Execution Conical Square: 6, 7, 8 & 9mm.1 x Double Ended Bit (Slotted 1.0x7mm and PH2).1 x 1/4in Bit Adaptor.