The is a professional and practical wireless serial 4 pin transceiver module, which is mainly made of durable hard PCB board and metal, and allows your device to both send or receive the TTL data via technology without connecting a serial cable to your computer. It works with any adapters, with coverage up to 30ft. Features - Model: . - - Mateiral: durable PCB board and metal. - Size: about 4.3*1.6*0.7cm ((board length 3.75cm). - and Wireless Serial 4 Pin Transceiver Module Compatible for Arduino. - Allows your device to both send or receive the TTL data via technology without connecting a serial cable to your computer. , ground, RX, TX and you can send data to/from . - Works with any USB adapters. - Default Rate: 9600,8,1,n default passcode: 1234. - Built in antenna. - Coverage up to 30ft. Specifications - version: + EDR - Operating voltage: 3.3V - Signal coverage: up to 30ft - Default Rate: 9600,8,1,n. Package list: 3 * Wireless Serial 4 Pin Transceiver Module Compatible for 3 * Connection Cable (Random Color)