ATMOS Chair 21 D is similar to 31 P/21 P models and features one-piece scratch proof and tear-resistant faux leather seat of 33 cm diameter with adjustable height regulation from 52 cm up to 68 cm, which is executed by gas-powered compression spring. The ultra-small diameter base (47 cm) permits it to be positioned very close to patients. The seat, available in various colors is also unaffected by disinfectants.