Standard Seals: Single seal for heating food applications, heating/cooling non food applications of non abrasive products (sauces, fruit preparations, MDM) rotating carbon seal face, stationary stainless steel seal bushing coated with chrome oxide hard face seals : single seal for abrasive or crystallized food products (chocolate, caramel) heating/cooling non food products rotating silicon carbide (abrasive) seal face, stationary stainless steel bushing coated with crome oxide.