Cheapest they have been.
Kidde Carbon Monoxide Basic Alarm Twin Pack.
With this Kidde twin pack of alarms you can keep your home and family protected from the silent danger of the highly poisonous gas carbon monoxide. Ideal for positioning in two areas of the home, should carbon monoxide be detected, an 85 decibel alarm will alert you.
Hush button operation.
Test button operation.
6 year sensor life.
Batteries required: 3 x AA (included) .
Size H14, W14, D3.8cm.
Manufacturer's 7 year guarantee.