1.High back ergonomic design of nylon main frame with good quality breathable mesh covered stitching, durable and environmental for using. 2. Comfortable seat: preformed high density sponge with soft fabric covered seat, last longer and nice design. 3. Armrest: pp armrest 4. Mechanism:tilting and lock mechanism 5. Gaslift: bifma passed gaslift with 120000cycles rotation(360degree)test and 100000times impact test 6. Base: 330mm nylon base, pass 1136kgs load bearing test. 7. Castors: nylon castors with bifma passed, 360degree easy rotating with smoothly moving, no noise & no damage to floor.