A stairlift is a mechanical device for lifting people up and down stairs For sufficiently wide stairs, a rail is mounted to the treads of the stairs. A chair or lifting platform is attached to the rail. A person on the chair or platform is lifted as the chair moves along the rail. Stairlifts are known variously as stair lifts, stair-lifts, chair lifts, stair gliders and by other names. This type of chair lift should not be confused with the chairlift used by skiers. The term stair climber can refer either to stair lifts, or more commonly to the exercise equipment by the same name.