Features: - Detects opening/closing using Hall effect sensor and reports it to your iOS device. Opening is detected by separating the sensor’s body and the magnet. Changing the state is indicated with one blink. - Detects tampering whenever the accessory is TechInfo: Power supply: 3.6V DC battery Battery type: ER14250 ½ AA EU directives compliance: - RED 2014/53/EU - RoHS 2011/65/EU Radio protocol:Bluetooth® low energy Radio frequency: 2.4 GHz Range:up to 50m (free range) (164 feet) Operating temperature: 0-40°C (32-104°F) Temperature measuring range: 0-40°C (32-104°F) Temperature measuring accuracy: ±0.5°C (±0.9°F) Dimensions (L x W x H): 71 x 18 x 18 mm (2.8 x 0.7 x 0.7 inch) Warning: Using batteries other than specified may result in explosion. Dispose of properly, observing environmental protection rules.