Battery operated three x AA. Low battery and fault warning lights. Memory. Audible and visual alarms. Test/reset button. Wall-mounted. Size: H12.5 x W10.4 x D4.2cm.
CommentsGood points: Alarm triggered within three minutes and noise level was over 85db during testing. Can be made tamperproof so batteries are not removed. Thorough instructions. Drawbacks: No display. Complicated system of flashing lights to indicate presence of Co, fault or low battery.