In April 8th 2020, the metal case designed for orange pi 4 board are finally here!
Why we design this case? As we get several customer requirement of orange pi 4 case.
This is metal case is designed for the Orange Pi 4 only. It reserves all the interfaces of the motherboard, supports the cooling fan, supports the extraction of the GPIO cable, and also reserves 2 antenna holes for you to replace the antenna that comes with the motherboard. 
What's Orange Pi 4？
It’s an open-source single-board computer. It can run Android 8.1、Ubuntu 16.04、Ubuntu 18.04、Debian 9 image. It uses the Rockchip RK3399, and equipped with Dual 4GB LPDDR4 , an optional 16GB eMMC flash
About how to connect the antenna, how to connect the cooling fan, how to set the heatsinks , you can refer to the below photo:
