KLIIG ECO 2 ADJUSTABLE LUMBAR is product #3 (below) with 3 major upgrades: 1). The lumbar is adjustable and not fixed. 2). The seat is much thicker and more comfortable. 3). The metal leg has been changed to nylon legs for safety & durability. Nylon legs will not cut your toes when you're walking around barefooted WFH. Also it will not rust. As a result of the upgrades, #3 has now become the most comfortable chair in this chair list. We highly recommended it if you're looking for a compact chair that is extremely comfortable. Can be used by all users. For actual product see the actual picture in the thumbnail above.