Features: High quality CNC aluminum alloy material, through oxidization and sandblasting process, more conductive to heat dissipation. Built-in heat conduction post for more effective transfer of the heat produced by the CPU. Dual cooling fans (optional) further enhances heat dissipation effect of aluminum shell. Open structure design makes sure no influence on the transmission of WIFI signals. All interfaces and slots in the aluminum box are perfectly fit for Raspberry Pi 4B. Complete with thermal conductive silicone and installation accessories. Specification: Condition: Brand New Item Type: Aluminum Alloy Protective Box Material: Aluminum Alloy Color: Black Item Size: Approx 8.5x5.5x2.5cm / 3.35x2.17x0.98in Fitment: Fit for Raspberry Pi 4B Option: Aluminum Box, Aluminum Box + Dual Fan Package List: 2 x Aluminum Housing 1 x Wrench 4 x Screw 3 x Thermal Conductive Silicone 2 x Cooling Fan (Optional) Note: 1. Due to the difference between monitors and light effects, the pictures may not reflect the actual color of the item. 2. Please allow slight error due to manual measurement. Thanks for your understanding.