Universal Security Instruments Hardwired Ionization Smoke and Fire Alarm with Battery Backup, Model 5304 Front-loading battery drawer makes it easy to replace battery without removing the alarm from the bracket Fully interconnectable with up to twenty-four USI-compatible devices Patented Quick Find alarm origination easily identifies the first alarm to sound in interconnected systems Universal mounting bracket fits any standard wiring junction box, single gang, round or octagon, up to 4-inches Comes with a ten-year limited warranty