Simplex 49SO-APPLW Wall Mount Addressable Speaker - Speaker Only - New In Box The Simplex 49SO-APPLW is a Wall Mount Addressable Speaker (S/O) notification appliance. This speaker uses a Simplex fire alarm control unit (FACU) IDNAC signaling line circuit (SLC) to individually power, address and control the Simplex 49SO-APPLW. Install wall mount indoor and addressable S/O notification appliances on standard 4 inch square 2 1/8 inch deep USA electrical boxes for flush installations, provided by others, or surface or weatherproof (WP) backboxes. NOTE: Select cover, mounting plate, and surface or WP box separately, if required. All fire alarm parts should be installed and tested by a certified fire alarm professional as required by local codes and NFPA. Disclaimer: We are not affiliated with any fire alarm manufacturers or dealers. We offer high quality new and seller reconditioned reliable fire alarm parts to help you maintain your existing fire systems. We buy, sell, and liquidate excess fire alarm parts. We are selling a huge amount of new alarm equipment! Please take a look at our other listings! *WE CAN WORK OUT A DEAL FOR BULK ORDERS* SHELF: A