Cables and pulleys were used long ago to transfer people and supplies across slopes or down steep slopes. Playgrounds and backyards would be the most recent places to take advantage of the daring cable device known as the zip line.
Charleston Home + Design Mag
A zip line kit consists of a stainless steel cable, a pully, cable clamps and a turnbuckle to twist the cable.
Verner Architects
Gravity allows daring passengers to glide freely from the top point to non.
John Prindle
Zip lines may be high and long or short and non; it requires more power from the user to move the pully at lower speeds.