Smart Electronic Devices Protect Your Doors and Windows Around the House: This set of four alarms protects your home in different locations: front door, balcony, garden, bedroom, and windows. Easy Installation: The alarms require no tools or cables. Simply attach them to the windowsill or door frame using the included adhesive tape. The magnetic system takes care of the rest. Alarms: Compact, practical, and discreet. Their white design will blend perfectly with the aesthetics of your home. Note: Make sure your apartment or house is properly equipped so that the security system prevents accidental activation (the distance between the transmitter and the receiver must not exceed 10 mm). Technical specifications Transmitter dimensions: 9 x 3 x 2 cm / Receiver: 5 x 1 x 1.5 cm Batteries: 2 x 1.5 V AAA batteries per siren (not included) Volume: 120 dB Maximum distance between transmitter and receiver: 10 mm Scope of delivery: 4 wireless sirens 4 magnetic receivers