POE HAT (B) for Raspberry Pi 4B/3Band,Power Over Ethernet HAT,Support 802.3af PoE Network,802.3af Power-Sourcing Equipment Required Integrates PCF8574 IO expander for I2C bus, providing pin P0 for directly fan control, and more spare IO pins 0.91Inch OLED, for monitoring processor temperature, IP address, and fan status in real-time Onboard cooling fan, allows auto running on powerup OR programmable control, configured by switch POE POWER INPUT:37V - 57V DC in. POE POWER OUTPUT:5V 2.5A DC out . OLED PIXELS:128x32. NETWORK STANDARD:802.3af PoE. OLED DRIVER:SSD1306. OLED DISPLAY COLOR:white. DESCRIPTION Power Over Ethernet: Providing Both Network Connection And Power Supply For Your Raspberry Pi In One Cable Cooling Fan: Allows Auto Running On Powerup OR Programmable Control, Configured By Switch Automatically Turn On/Off Depending On The Raspberry Pi Processor Temperature Onboard PCF8574 Chip: PCF8574 IO Expander For I2C Bus, Providing 8 IO Pins, Of Which P0 For Fan Control And Extra Spare Pins On Solder Pads (P1-P7, INT) PoE (Power Over Ethernet) capability,802.3af-compliant Fully isolated switched-mode power supply (SMPS) colour: blue Material: PC board and metal size: 65x56.5mm Package Contents: 1xPoE HAT Expansion Board 1xScrews kit 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.