4520-00-371-4534 (G1-12040)
4520-00-371-4534 is equivalent to manufacture part number 11115. It is a sight tube window 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.