MICRO SWITCH GKM Series Miniature Key Operated Safety Switch, 2NC Direct Opening, Slow Action, 1 m Bottom Exit Cable, Plastic Housing, Silver-Nickel Contacts The GKM Series Global Miniature Safety Key Interlock Switch is designed for use on machinery where key removal brings the machine to an immediate safe condition. The GKM Series provides enhanced operator safety when added to hinged or sliding guard doors, screens and protective covers on enclosures. Key sold separately. UL, CE, SIL 3 capable.