The Air-Chair allows you to spend more time where it counts; at the eyepiece, and more comfortable time at that.  The soft, rotating seat adjusts from 21.0-28.0" (53.3-71.1 cm) and features a pneumatic piston for smooth lifting.  The legs fold up and the seat is easily removed for transport.  Having those critical range of height adjustment in a chair used for observing the skies makes for more pleasure night after night.