Horizontal ribbing runs across the 18 by 18.5 inch backrest, a detail borrowed from mid-century seating that also breaks the surface into segments so the panel flexes with the shoulders. Behind it, an S-shaped contour fills the lumbar gap, and integrated armrests sit 19 inches apart on the inside. PU leather over elastic sponge takes daily use and cleans with a cloth. Seat height covers 18 to 23 inches, a full 5 inches of travel, and the back rocks through an 18 degree arc from upright. The five-claw metal base handles 330 lbs and the gas cylinder lifts smoothly. With a 17.5 inch square seat and a 23.5 by 21.5 inch footprint, this fits a small home office; assembled weight is 26.5 lbs.