A five leg tubular base with 18" diameter footring, 22" leg spread, A concave vinyl upholstered seat is 18 1/2"W x 16 1/2"D x 3" Thick. Backrest is 14 1/2"W x 9 1/2"H with lumbar support. A patented Class 100 (ISO 5) Filtration system. Utilizes a filtration system within the seat. It traps particulates while permitting the seat to conform to body shape. The filter allows unrestricted air flow with a filter permeability of 230 CFM/ft 2, The polypropylene filter traps particles 0.1 microns and larger for use in Class 100 (ISO 5) Cleanrooms (federal std. 209B) Performance tested and certified by an independent research laboratory, Test results available. "Soft-Touch" pneumatic adjustment mechanism. Exposed parts plated or aluminum to minimize contamination. 4 base designs. CODE VUV