Our 440T Slamlock™ Trapped Key Interlock Switches combine the features of trapped keys with tongue actuated interlocks. When the actuator is inserted into the interlock (guard closed), the trapped key can be rotated and removed. With the key free, the actuator cannot be removed. This locks the guard door. The trapped key must be re-inserted and rotated 90° to unlock the guard door. Slamlock Interlock Switches are available in mechanical, electrical, and solenoid versions.