GP Lithium 9V Block Batteries Long Life 9 Volt Lithium Li-MnO2, 10 Pieces 9 V Block Lithium, Ideal as a Smoke Alarm Battery, for Fire Detectors, Microphones etc: Amazon.de: DIY & Tools
ANSMANN 9V Block Alkaline longlife (8 Stück) - ideal für Rauchmelder, Alarmanlagen, Brandmelder 9 Volt Block E Batterie, 9V Alkaline Batterie, 9 Volt | MediaMarkt
9V Lithium Battery | Non-Rechargeable for Smoke Detector Fire Alarm – Enegitech