Robinair's 100343 is a 1/4 inch MFL x 1/4 inch MFL Filter-Drier for use with Robinair RG3, RG6 and other refrigerant recovery machines. Designed to be placed in line between the inlet fitting on the AC machine and the outlet fitting on the manifold gauge set. Filter-Drier prevents contamination from entering the refrigerant recovery unit, which reduces the risk of damage to both the unit and the system being serviced. If recovering more than one type of refrigerant with the same recovery machine, a separate filter drier must be labeled and used for each refrigerant type. Sold individually.