The Reliance 4246 series is a Pneumatic Stool featuring a 15" diameter seat with a 2' high density polyfoam cushion. Height is controlled with a convenient lever. Lift the lever and a pneumatic device assists in elevating the seat as you take your weight off the stool. To lower while seated, raise the lever and the stool descends gently to desired height. A contoured, padded backrest adjusts horizontally and vertically for optimum back support.