Feature: 1. Ultra thin design, lightweight and durable, open slotted design, can ensure that our shell will not affect the wifi Bluetooth signal transmission. 2. Built in heat conducting column, fast heat dissipation, cooling fan can be installed, all ports and slots of the shell are suitable for Raspberry Pi 4 Model B. 3. Easy to produce a dense and firm protective film on the surface, which protects the substrate from corrosion, has strong wear resistance and is not easy to rust. 4. For Raspberry Pi CPU heat is transferred to the aluminum alloy shell through the heat conduction column, and the dual fans further enhance the heat dissipation effect. 5. Oxidation sandblasting process, high hardness, strong pressure resistance, metallic luster, aluminum alloy material is more conducive to heat dissipation. Specification: Item Type: Aluminum Alloy Case Set Material: Aluminum Alloy Purpose: Radiator Shell Accessories Adaptation PCB: For Raspberry Pi 4 Model B Shell Size: Approx. 8.5x2.5x5.5mm / 0.3x0.1x0.2in. Package List: 2 x Metal Shell Accessories1 x Sticker4 x Screw1 x Hex Wrench Note: 1. Please allow 0‑1 inch error due to manual measurement. Thanks for your understanding.2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.