4520-00-009-7328 (N78522A)
4520-00-009-7328 is equivalent to manufacture part number 78522. It is a peep sight glass and is classified under Federal Supply Class 4520 (4520 - Space and Water Heating Equipment), stocked for defense, aerospace, MRO, and industrial maintenance applications. This item is cataloged in the NATO supply system under 4520 - Space and Water Heating Equipment and is available through NSN-PARTS for U.S. government MRO, and commercial procurement.