1. Supply voltage 3.2V - 5.5V. (If you want to work in the module launch state for a long time, it is recommended when the supply voltage exceeds 4.5V series with a 1N4007 diode, to avoid heating module built LDO) 2. Default communication distance (open test): about 600m (adjustable to achieve the maximum communication distance of 1000m, the air baud rate 5000bps). 3. The default idle current: 16MA (modules in different operating current of the different operating modes). 4. Operating frequency range: 433-473.0MHz, up to 100 communication channels. Maximum 100mW transmit power (can be set) 5. The module supports software upgrades. The default factory settings: operating mode FU3, baud rate 9600bps, communication channel CH001 (433M). colour:Blue Material:plastic size:27.8 x 14.4 x 4mm Package Contents: 3 x Wireless Serial Port Module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.