This is an optional upgrade for Tom3D's camera slider. I found the open builds platform fiddly. This replaces the open builds platform with a single piece which incorporates the belt clamp in one printable part. There are two versions of the platform one has a larger hole for a 3/8" bolt, that some ball head mounts use for a nice sturdy coupling. The other is a standard 1/4 bolt hole.
The piece is easy to install but does require the slider to be disassembled at one end to allow for the belt to be installed.