Module is sensitive to static electricity, please reduce the touch to the module chip parts, so as to avoid loss of procedures Module antenna part of the following can not be deposited copper, can not be traced, otherwise it will affect the signal, Suggest that the antenna part of the floor hollowed out, the antenna as close as possible to the edge of the board, or insert the way Module power loss memory, parameters and matching information will not be lost, so if you want to connect a device, please clear the module pairing memory. Product Parameters: Model: HC-08 Working frequency band: 2.4G Communication interface: UART3.3VTTL level Working voltage: 2.0 ~ 3.6v RSSI support: not supported Communication level: 3.3v Transmit power: 4dBm (max) Transmission distance: 80 meters Emission current: 31.6mA Module size: 26.9 * 13mm Air speed: 1Mbps Antenna interface: built-in PCB antenna Sleep current: 0.4uA Receiver sensitivity: -93dBm @ 1Mbps Working humidity: 10% to 90% Storage temperature: -40 ℃ ~ 85 ℃ Working temperature: -25 ℃ ~ 75 ℃ Received current: 15.8mA Color: Green Material: plastic Specification: Without base plate. Package Contents: 1*HC08 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.