Feature:1. This product is suitable for Raspberry Pi 3B+/4B Power over Ethernet (PoE) expansion board and supports 802.3a network standard. If you have a PoE router or switch that supports the 802.3af network standard, then take it with you and merely need a network cable to connect to allow your for Raspberry Pi to achieve networking and power supply.2. In the future, the new version of for Raspberry Pi can be supported as long as it is compatible with the old version, and the onboard OLED display can display temperature and IP in real time address, fan running status.3. Based on for Raspberry Pi 40pin GPIO interface, the product is suitable for Raspberry Pi3B+/4B and support PoE power over Ethernet and 802.3af PoE network standard.4. Using isolated switch mode power supply (SMPS), onboard 0.91inch OLED can give real-time display of temperature, IP address, fan running status, etc.5. Onboard cooling fan, with fan switch, can be set to run on power or pin programming control. Onboard PCF8574, 8 channels/o ports are expanded through I2C, which can directly control the fanSpecification:Item Type: Cooling fan module.PoE Power Input: 37V~57V DC inputOLED Size: 0.91 inchesPoE Power Output: 5V 2.5A DC outputOLED Resolution: 128 x 32Network Standard: Support 802.3af PoEOLED Driver Chip: SSD1306OLED Display Color: WhitePackage List:1 x POE HAT (B)1 x Screw Package