M3SSK4-101 is a three-position key-operated selector switch designed for industrial control panel applications. This modular pilot device features a spring return mechanism from position C to B, with the key removable only in position A, and uses key release code 71/Ronis 455. The switch is part of ABB's Modular Range of 22mm pilot devices and features a black plastic bezel as standard, with an optional chrome metal bezel available. It is designed for modular assembly with separate contact blocks and holders, allowing flexible configuration for various control requirements. Common applications include machine control, process automation, and equipment where secure key-operated switching with position-specific key removal is required.