The Knipex DoubleJoint Control Cabinet Key has four different zinc die-cast key profiles and a magnetic bit adapter for 1/4in bits. The Key is suitable for locking systems in electrical engineering, the supply of gas and water, air conditioning and ventilation systems, industry, technical installations in buildings, etc. Specification Capacity Square 5.0-8.0mm, Double-bit Key 3-5mm, Triangular 7.0-9.0mm. Total Length 97mm. (3.82in).