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 valvesmains switch boards etc supplied with a securing chain it has the following functions 3 x square 5 7 8mm1 x triangular 9 10mm 1 x two way 3 5mm1 x long execution conical square 6 7 8 9mm1 x double ended bit slotted 10x7mm and ph21 x 14in bit adaptor