BOSS Office Products MESH CHAIR W/KD047 MECHANISM,034 ARM, MESH SEAT BL-152 Thick padded contoured seat and air mesh back with built-in lumbar support. 2 to 1 synchro tilt mechanism with adjustable tilt tension control. Breathable mesh fabric seat with ample padding. Adjustable height armrests with soft polyurethane pads. Seat tilt lock allows the seat to lock in the upright position. Padded back frame. Pneumatic gas list seat height adjustment. Large 27" nylon base for greater stability. Hooded double wheel casters.