Material: stainless steel Size: 115*42*13mm Color: silver/golden Power supply: 3 x AA batteries Battery life: 10-12 month approx. (depending on usage) Low voltage alarm function: voltage lower than 4.8V External power interface: yes Working temperature: -20 ℃ ~ +65 ℃ Working humidity: less than 98%RH Lock body material: fire rated plastic