I did not want hard wire.

I have a home with hard-wired and battery back-up smoke detectors installed at initial build

The package for the 8 detectors that I purchased identifies them as Model SA305CN which is designed to be "hard wired" to 115Volt AC current.

Unusable battery wiring missing

One clarification, even though the back has a receptacle for a hard wired setup, it doesn't actually have any connectors

Was missing the battery wires

The ULTRALIFE brand lithium battery manufacturer warrants them for 10 years of backup power - ONLY when they are installed in detectors that are "hard wired" to 115 Volt AC electrical power.

I would have gone with the type you wire into your home electricity, but the locations I needed to place the detectors were not conducive to hard-wiring

I bought this to replace a hard wired unit

I disconnected the hard-wired alarms in my 15 year old condo and put these in their place.

Compliments two hard wired photoelectric smoke alarms

My bad as I waited too long to return.