LANGRIA Mid-back Ergonomic Office Chair Mesh Chair Swivel Computer Task Chair with Adjustable Arms, Max 285 lbs,Black Flexible Structure: The pneumatic gas lift system allows for easy adjustment of seat height by flipping the lever up or down; armrests can be adjusted to 3 dimensions (up and down/forth and back/left and right); 360-degree swivel Knee Tilt Mechanism: the backrest can be reclined to 2 different angles (90,110), push the lever in to lock the chair in an upright position (90), pull the lever out to unlock the chair Breathable Comfort: the premium PP backrest with Korean mesh fabric is flexible, giving you a cool and comfortable sitting experience by promoting good air flow and eliminating sweating and moisture; the contoured mesh seat is soft and comfortable Durable Materials: With premium PP backrest combining Korean mesh, mesh upholstered seat, contoured armrests, heavy-duty nylon seat base, and flexible nylon casters, this chair is designed to give you long lasting joy High Quality Guaranteed: LANGRIAs mesh task chair meets BIFMA standards and supports up to 285lbs. of evenly distributed weight, its explosion-proof base plate with sturdy legs increases safety and stability Maximum Overall Dimension: W x D x H 24.61  25.00 (36.22-39.96) in. Chair Height: 36.2-39.9 in. Seat Dimension: W x D x H18.90 x 18.11 x (17.52-21.46) in. Back Dimension: W: 18.11 x H: 20.47in. Net Weight: 24.25 lbs