Features: Made of high quality ABS engineering plastic material, strong and durable, fine workmanship and long service life. Adopts imported procession chipset, high-performance noise reduction coding and decoding circuit, fast heat dissipation and strong stability. The launching distance of the receiver is very far away. The actual distance is affected by the nearby environment. Convenient for Guests. They can rest in the empty space after ordering, no need to wait in line at the bar. Suitable for SU-668 model wireless guest queuing system. For restaurant, hospital and other places. Specifications: Item Type: Coaster Receiver Color: Black / Red Size: Approx. 78 x 15mm / 3.07 x 0.59 inches Working Voltage: DC3.7V (Rechargeable Battery) Charging Voltage: DC5V 4A Working Frequency: 433.92MHZ Working Current: 75±10mA Standby Current: <12mA±3mA Decoding Method: Learning Code Battery Capacity: 360mAh Package Includes: 10 Pieces Receivers note: Please allow 1-2cm errors due to manual measurement. Because of the different display of each computer, the pictures may not reflect the actual color of the item.