4730-01-429-3355 (SM-126-D)
NSN 4730-01-429-3355 (NIIN 01-429-3355) is an air trap in Federal Supply Class 4730, Hose, Pipe, Tube, Lubrication, And Railing Fittings — a device used to automatically vent air from water or vent gas from any liquid in a pipeline or closed vessel. Manufacturer part number SM-126-D; also referenced as 211 1/2 BODY, SM-126-D NO-3 (Armstrong International Inc).
Key specs: 250 psi maximum operating pressure; full characteristics table below. NIIN assigned April 1996; DEMIL A (none required); unit of issue EA (each), $85.23 gov standard price; ships at 3.64 lb / 0.0986 cu ft.