The 3-piece FRL air treatment assembly in sizes G1-1/2 and G2 consists of a filter with a metal bowl, a regulator with a pressure gauge, and a lubricator with a metal bowl. It is available with two types of fittings: simple nipples or 3-piece fittings. The first type helps reduce length dimensions, while the second simplifies maintenance operations. The lubricator is available with two types of level measurement: minimum level and continuous level monitoring.