Immunity Steel™ Pumice Cup, Modified Immunity Steel™ Pumice Cup, Modified PCUPM Used to hold prophy paste or medicaments. Made of corrosion resistant, acid-proof stainless steel. Where to Buy x Category Dealer PartnersSales RepresentativeStrategic MarketsSchools RepresentativeAccutron™ Equipment Sales Zip Code Find RepresentativeReset Select a category, input a zip code and click on Find Representative, or explore the complete list here.