New ES900TX module with a 2006 Fan, it would working automatically when the TX power is 250mw. Source on GitHub: https://github.com/ExpressLRS/ExpressLRS ExpressLRS community:ExpressLRS - High Performance Radio Control Link As ExpressLRS firmware is constantly being improved and updated, we strongly recommend that you use the ExpressLRS configurator update firmware to get the best experience Configurator https://github.com/ExpressLRS/ExpressLRS-Configurator/releases Firmware https://github.com/ExpressLRS/ExpressLRS/releases Specifications: ES900TX: MCU:ESP32+ESP8285 Dimension: 55mm x 39mm x 11mm Weight: 9.2gram (only the TX module) Antenna connector: SMA VCC input: 5~13v, Recommend 5v~9v RF Frequency: 868MHZ Maximum Output Power: Less than 33dBm(For 27dBm operation, we recommend add a fan for force cooling) Wifi update firmware function for ES900TX would be available in a short time. Material: plastic+metal Color: as shown Package Contents: 1 x 868MHZ ES900TX 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.