filter drier 052S 100 % molecular sieves — Castel, OEM manufacturer part number DF305E2S. Verified technical data: Product description = 1/4", 80 bar, 80cm3. Applications: refrigerant liquid-line filtration, moisture and acid capture in HFC / HFO refrigeration systems. Castel is a leading manufacturer in this segment; the DF305E2S sits within the Castel filters & driers range.