Crosstex™ Ultra™ Earloop Mask Crosstex™ Ultra™ Earloop Mask GCFCXU ASTM LEVEL 3. Ideal for procedures where heavy to moderate amounts of fluid, spray and or aerosols are produced. 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.