I've used this for six months. I bought this because the one I had was deteriorated during a 6th-grade safety inspection at school. I no longer need it, so please use it for crime prevention. I've replaced the batteries with new ones ╰(*´︶`*)╯ It's ready to use immediately. Color: Blue Brand: ELPA Battery Description: Alkaline Number of Batteries: 2 Alkaline button batteries Voltage: 3 volts (DC) Noise Level: 50 decibels Search or ask a question Product Details Top Highlights to • Size: Height 4.9 x Width 2.4 x Depth 2.1cm • Weight: 0.023kg (including batteries) • Material: ABS resin • Country of Origin: China • Accessories: 2 alkaline button batteries LR44 (test batteries included) • Volume: Approximately 90dB/50cm • Battery life: Approximately 50 minutes of continuous alarm (varies depending on battery performance and usage) • Operating temperature range: 0°C~40°C