These 17-1/2" heavy-duty lift lid chair desks are designed to withstand everyday abuse. These student desks feature a 21-1/2" x 16" x 4" storage compartment with 20-gauge embossed steel, full-length piano hinge, two friction hinges and two rubber bumper cushions. Chair desks also feature a 3/8" thick solid plastic seat, and a solid plastic writing surface. Optional wire book baskets can be added on as well.