This thing replaces the backplate of your steam controller. It allows you to attach this smartphone mount to your steam controller: amazon.com: https://www.amazon.com/Controller-Joso-Adjustable-Smartphones-Playstation/dp/B01EL5A5AY/ amazon.de: https://www.amazon.de/gp/product/B00VJKS1H4/ To install it, the only tool you need is a Torx 6 screwdriver. Disassembly video here: https://youtu.be/yCzPAv0p-HU?t=30s