Product Characteristic: Capacity: 0.5-20 t Easily adjustable (round nuts) to fit a wide range of beam widths. Excellent rolling features due to machined steek wheel mounted on prelubricated, encaosulatd ball bearings . High efficiency in transmission and minimum hand-pull and can travel on bends of small radius Usable on straight or curved track. Simply remove end nut and adjust spacers. Can be installed or removed from any point in the track.