Sit stand design : Rounded seat in soft polyurethane, with integral gas lift heif=ght control handle to adjust the seat to the most comfortable level. Frame designed to allow maximum free movement. Adjustable height seat - swivel and tilt : Tubular frame in lacquered black epoxy resin. Swivelling and tilting polyurethane seat. Ratchet height adjustment. Sit stand with lumbar support : Ergonomically designed saddle-style seat with lumbar support. Gas lift height adjustment.