D-Series air preparation units come in three body sizes and offer flow capacities from 24 to 406 scfm. Inch and metric series are available with port sizes from 1 /8 to 1 in. NPT. Choice of individual units (FRLs) or factory-assembled combinations available. The units are made of durable, lightweight zinc and aluminum with polycarbonate filter bowls and metal bowl guards for long life in harsh environments. They provide two pressure ranges (12 and 7 bar) and a full range of filtration levels (40, 5, 1, and 0.01 µm).