The Insta360 ONE R Mounting Bracket provides a 2-prong mount for the ONE R system. It fits the Core module, a second module of your choice, and the Battery Base, and it lets you mount them on various 3-prong supports. It also allows them to be waterproof. All the modules are waterproof down to 16' as they are, without a housing, but only after being assembled and installed together on this Mounting Bracket. Additionally, the Mounting Bracket comes with a small selfie stick adapter that provides a 3-prong mount on top and a 1/4"-20 threaded hole on the bottom. Using this adapter, you can attach the Mounting Bracket to various 1/4"-20 supports, such as selfie sticks and handheld gimbals.