Ergonomic Mesh Computer Office Desk Task Midback Task Chair Metal Base Maximum Dimensions: 16.7 inches W x 21.7 inches D x 35.6 -40.4 inches H Seat Width:16.7 inches Seat Depth: 16.3 inches Seat Height: 18.3 inch - 23 inches Back Width: 15.6 inches Back Height: 17.7 inches Height adjustable from 35.6" to 40.4" to meet needs The knee-tilt Mechanism can pull the lever outwards to recline freely and push the lever inwards to lock in the 90 degree upright position The tilt tension control knob below the seat can be rotated to accommodate different size/weight users Heavy Duty: solid structure with high capacity