Battery operated - three AA. Low battery warning. Audible and visual alarms. Test/reset button. Wall-mounted. Size: H13 x W10 x D4.2cm
CommentsGood points: Alarm triggered within three minutes and noise level was over 85db during testing. Battery can be refitted without removing from wall. Thorough instructions. Drawbacks: No display. Complicated system of beeps and flashing light to indicate raised levels of CO or faults.