YJ139-LA39 Emergency Switch Technical Specifications Mounting Hole Size: 22 mm diameter Max Voltage (Ui): 600V AC Current Rating (Ith): 10A Action Type: Latching / Self-locking (Push to stop, twist/rotate to reset) Contact Options: Modular configurations (commonly 1NC, 1NO+1NC, or 2NC) [1, 2, 3] Installation and Wiring Cutout: Drill a clean 22 mm hole on the control box or machine panel. Disassembly: Separate the contact block base from the plastic/metal operator head using the base clips before mounting. Wiring: Connect your safety control loop or stop circuit to the Normally Closed (NC) terminals for safe interruption upon actuation. If you need help, tell me: What is the contact configuration (1NO+1NC or 2NC) you are trying to wire? Are you replacing an LA38 or LA39 model?