Matelec FSA-25000 Photoelectric Smoke Alarm, Detector, 240V with 9V Alkaline Battery Back Up, 85dB @ 3mtr, 135mm Dia x 54mm, Surface Mount, White

Features:
• Interconnectable with up to 20 units
• Energiser 9V battery included
• Separate hush/test button
• Hinged detachable base - easy push button open
• No Battery', 'No Close' feature
• Loop terminal provided
• Mounting holes line up with standard plaster brackets
• Base recessed for mains cabling - no need for large ceiling cut-away
• LED indicators
• Low Battery' audible warning
• Improved resilience to EMI interference
• Insect resistant sensor