Viper In-Line Filter For VR-7000 VR-6000 VR-4550 VR-4500 Series Recovery Recycling Units. Specifically formulated drier desiccant to trap acid and particulates and is formulated to remove water from the refrigerant. You must change the filter-drier to assure adequate moisture and contaminant removal. Typically, you can recycle up to 150 pounds of R-134a or 200 pounds of R-22 refrigerant between filter changes.