4820-01-283-1819 (1750FB-2.50IN)
4820-01-283-1819 is equivalent to manufacture part number 1750F. It is a vent-check valve and is classified under Federal Supply Class 4820 (4820 - Valves, Nonpowered), stocked for defense, aerospace, MRO, and industrial maintenance applications. This item is cataloged in the NATO supply system under 4820 - Valves, Nonpowered and is available through NSN-PARTS for U.S. government MRO, and commercial procurement.