Protector PVC Acid Digestion Laboratory Hoods feature washdown systems, integral work surfaces and drainage troughs so that they may be thoroughly rinsed after each use. Their liners of Type 1 unplasticized polyvinyl chloride are designed to withstand reaction from strong acid. These hoods feature Lexan® polycarbonate sashes, which are recommended for applications involving the use of acids including hydrofluoric acid but not perchloric acid. The Lexan material does not fog or etch when exposed to hydrofluoric fumes.