Features: Guests can sit down to rest after ordering and no need to wait in line at the bar. It is very convenient for guest. Specification: (Keyboard transmitter) Size: about 162 * 112 * 72mm / 6.3 * 4.4 * 2.8in Working voltage: DC12V Working frequency: 433.92MHZ Working current: 100mA±30mA Standby current: <24mA±5mA Coding method: learning code (receiver) Color: black Size: about 80 * 80 * 10mm / 3.1 * 0.3in Working voltage: DC3.7V (rechargeable battery) Charging voltage: DC5V Working frequency: 433.92MHZ Working current: 75±10mA Standby current: 10mA±5mA Decoding method: learning code Battery capacity: 360mAh Function: charge only, low power prompt, online search, vibration, sound, light rotation, free to switch prompts, maximum support 999 discs High-end professional processing chip: imported processing chipset, high-performance noise reduction coding and decoding circuit, fast heat dissipation and strong stability Package List: 1 * Keyboard Transmitter 20 * Receiver 2 * Charging Base 3 * Power Adapter 1 * Manual