Power supply voltage : 3.2V~5.5V.(if the modules working long hours in emission state, suggested that when the power supply voltage is 4.5 V you need concatenating a 1N4007 diode to avoid module built-in LDO got fever) Default communication distance : about 600 m (communication distance is adjustable up to 1000 m, air baud rate 5000 ). Default idle current: 16 ma (modules in different working mode of different current). Operating frequency range (433.4 473.0 MHz, as many as 100 communication channel) maximum 100 mw fired power (can be set) Module supporting software upgrades. Default factory Settings: working mode FU3, baud rate 9600 , communication channel CH001 (433.4 M) Module size: 27.8mm x 14.4mm x 4mm Material: PCB colour: blue Package Contents: 2 x 433Mhz SI4463/SI4438 Wireless Module Serial Port 1000M -12 Only the above package content, other products are not included. Note: Light 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.