The Model 28087 mobile storage tool cart for the cleanroom environment is 304 stainless steel body and drawers with a No.4 brushed finish with a 125 pound drawer capacity, The casters are a 5 x 1 1/2" non- marking polyurethane caster with 7 drawers. Certified Class 100 (ISO 5). Optional push button lock on Class 10 (ISO 4) units.