Mid-back chair frame features a mesh back that allows air to flow freely when you're seated to help you stay cool throughout the day. Lumbar support offers ergonomic support for your lower back to help prevent strain through extended seating. Ratchet back device allows you to adjust the back height to meet your specific requirements. Seat and back angle can adjust independently for maximum comfort. Chair frame also includes pneumatic seat-height adjustment, seat slider to adjust seat depth, 360-degree swivel, tilt tension and more. Arms adjust in height and width. Chair frame is designed for Lorell Conjure Bonded Leather Seat Cushions or Conjure Fabric Seat Cushions (each sold separately). Lorell seat cushions come in four colors: black, gray, navy and red.