Alera Wrigley Series 24/7 High Performance High-Back Multifunction Task Chair, Supports 300 lb, 17.24" to 20.55" Seat, BlackErgonomic design combines with high performance functions for all day comfort. Multi function mechanism allows back angle adjustment relative to seat, adjustable and forward tilt. Waterfall seat edge reduces pressure at the back of knees. Padded slant T arms are height and width adjustable. Impact resistant molded plastic shell. Five star base with casters for easy mobility.