Feature: 1. This product is suitable for RPI 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 RPI to achieve networking and power supply. 2. In the future, the new version of for RPI 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 RPI 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 fan Specification: Item Type: Cooling fan module.PoE Power Input: 37V~57V input OLED Size: 0.91 inches PoE Power Output: 5V 2.5A output OLED Resolution: 128 x 32 Network Standard: Support 802.3af PoE OLED Display Color: White Package List: 1 x POE HAT (B)1 x Screw Package