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 .Speed Adjustable Fan---It provides an ultra-thin 4007 silent fan to 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 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:BlackMaterial:plasticPackage Contents:1 x Fan Expansion BoardOnly 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.