Universally applicable cross-shaped key for locking systems in the fields of gas and water supply, electrical, industrial, air-conditioning and ventilation, sanitary installations, electrical cabinets, etc.; includes 4 inserts: square 5,7 and 8 mm, triangular in 8/9 mm and tapered square for sizes from 4 to 10 mm, is delivered with bit adapter for 8 mm square and double bit for Phillips screws size 2 and slotted screws 1.0 x 7 mm