The Alpha Communications SF118 Series Emergency Switch is available in two models and features a rugged, long-life, positive-acting switch mounted on a durable ABS white plastic faceplate. Signaling an emergency requires just a short pull on the 6' long nylon cord, in any direction. The signal cannot be canceled except at the point of origin. The SF118/2C provides two circuits to operate 1- 2 signaling devices, such as a remote annunciator lamp, and a corridor dome lamp. The SF118/4C provides two additional signaling circuits to operate additional options such as floor bell(s) and individual apartment electric door openers, as needed.