material: metal Keyboard size: 100mm (H) * 240mm (W) Keyboard position: 100mm from the bottom of the emitter Projection surface: non-reflective, opaque surface Operating surface: any plane Battery: rechargeable lithium battery Battery capacity: 500mhA External power supply: USB power supply / less than 5V1A Interface: USB interface Bluetooth: V3.0 Frequency range: 2402-2480MHz