Stack Chair adds a stylish look to any space without sacrificing comfort or functionality. Seat and back are made of polypropylene for superior durability and lumbar support. Solid, chrome frame with a sled base provides optimal stability. Perforated back maximizes airflow and circulation for added comfort. Sculpted back has an opening to make stacking and portability easy. Stack chairs up to 16 high on Boss Dolly (not included) or five high on the floor to save storage space. Ganging clamps (not included) can be attached to multiple units at the bottom of the leg. Chair holds up to 275 lb. and is Mas Green certified to reduce chemical emissions indoors.