Hansen HK Series quick disconnect couplers are equal to Aeroquip FD45 Series and Gates G94511/G94521. "Series HK Couplings are the most versatile couplings available and are suitable for use with various liquids, chemicals, steam, gases and vacuum. Series HK couplings conform to the dimensional requirements of ISO 7241-1 Series B. Body sizes range from 1/8 [inch] to 1 [inch]." Source: Hansen QD Coupling Catalog, 2010, pp. 46. Updated 10:49 PM 6/24/2010.