The Skate Dolly Kit is based around three 1/2 tubes with skate wheels attached. With an HIR rig you can swap out the handles and put these wheeled tubes in place another wheel must be added to the rear, the configuration of that will depend on the model of rig you own
This creates a skate dolly that can go forwards, sideways or eve turn around the lens or circle the subject. Skate dollies work best when used on an extremely flat surface such as a marble kitchen counter.
For RnG rig..
An earlier and more costly version used spuds, the functionality of the current version is the same as in the video, apart from more height options are possible!