Hydraulic Diagonal Line Adjustable Square Bar Stools Red (Set of 2)The bar stool is ergonomically designed L shape, which is more ergonomic ; The seat cushion is made by PU Leather and Sponge, comfortable enough The gas lift mechanism which is need remove the black cap before assembly the bar stools, and then everything is perfect; Check all parts before assembly the bar stools The bar stools is adjustable from 21. 5 inches to 31. 5 inches, which is not including the thin of the seat cushion, so you need to plus 2"