0.91 Inch OLED Display---This is a 40pin HAT type expansion board, which provides a 0.91 inch display screen connected to the I2C pin;The display information can be customized through the program. Speed Adjustable Fan---It provides an ultra-thin 4007 silent fan to provide heat dissipation support. Programmable LED Indicator---There are 4 customizable LED lights on the back of the board. You can also control the lighting mode of the LED lights through simple programming. GPIO expandable interface---The previous HAT board design is used. The 40Pin GPIO can still be easily accessed by users. The new fixing avoids the risk of short circuit caused by metal parts and provides a good appearance design. Note: board is not included! color:Black Material:plastic Package Contents: 1 x Fan Expansion Board Only the above package content, other products are not included. Note: Light 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.