The BRK & First Alert 0827/SA350B is a Single Alarm (SA) unit with a 10-year, Tamper-proof, Lithium battery. There are no pins or connector on the back of the unit. It cannot be interconnected to other smoke alarms. It cannot be connected to 120 Volt AC Power.
According to the Specifications sheet and User Manual , the model number is 0827 and the catalog number is SA350B. The tag on the back of the unit also says Model 0827. There is a BRK Model No. SA340, so I am not sure why or if BRK is changing how they choose model and catalog numbers.
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All I used was a small screwdriver to push the plastic taps inward so I could open this unit. There was another plastic tap holding the battery in place. Afterwards, I did reinsert the original battery, but I could have just as easily inserted an alkaline 9-volt battery. The back of the box and Specification Sheet [1] say "meets code for sealed, tamperproof, 10-year battery". I was expecting more of a deterrent.