The double slider uses a unique tracking mechanism that allows the rails of the slider to move with the camera when mounted on a tripod. ES35 gives the slider 17.3" of sliding range in a unit that is only 13.8" long heads. Specification :- Model No - ES35, Slider Length :- 1.6ft/35cm, Slider Range on ground :- 22cm, Net Weight :- 1.7kg