5640-01-006-5754 (HH-I-573)
NSN 5640-01-006-5754 (NIIN 01-006-5754) is a thermal insulation sleeving in Federal Supply Class 5640, Wallboard, Building Paper, And Thermal Insulation Materials — a rigid or flexible item composed of one or more materials, having uniform inside and outside diameters in the entire length. Manufacturer part number HH-I-573 (Federal Specifications Promulgated, CAGE 81348); also referenced as ASTM C534 (American Society For Testing And).
Key specs: not rated flammability; full characteristics table below. NIIN assigned July 1975; DEMIL A (none required).