ActronAir Filter Drier R410A 3/8" (Emerson BFK-163S) removes moisture and particulate contamination from the R410A refrigerant liquid line on compatible ActronAir split ducted systems, protecting expansion devices and compressor valves from moisture-induced acid formation and particle wear. Replace the filter drier whenever the refrigerant circuit is opened for component replacement -- any circuit opening exposes the drier to atmospheric moisture and saturates its desiccant capacity. Isolate power and recover all refrigerant before replacing any filter drier components.