The DBF series is designed specifically for heat pump or reverse cycle application. External check valves are not required since they are incorporated within the filter dryer shell. The core design filters out contaminant particles down to 25 microns. 100% copper sweat or nickel plated flare fittings. Desiccant core provides reliable and effective, removal of solid contaminants, acid and moisture. Provides three times the filtration as the standard bi-flow. Core is cushioned in fiber gaskets to protect core and to insure trouble-free performance. Powder paint exterior coating surpasses 500 hr ASTM salt spray test and resists corrosion.