Finder 12.81.8.230.0000 Digital Time/Astro-Switch 16A 1 CO (SPDT)
The back-up battery is easily replaceable from the front of the unit. This is for mounting on 35mm DIN rail. 1 CO (SPDT). Switching current: 16A. Manufacturer's part:Finder 12.81.8.230.0000. Switching capacity: (AC1) 16 A/250V AC.