MIL-C-38479 Revision C, March 30, 1972
COUPLING ASSEMBLIES, QUICK DISCONNECT, FUEL GRK-15/S32R AND GRU-13/E
The GRK-15/S32R and GRU-13/E coupling assemblies are intended for use between fuel hoses and a Type D-1 pressure fuel servicing nozzle in accordance with MIL-N-5877, as follows:
a. The GRK-15/S32R coupling assembly is for use with a 3-inch hose.
b. The GRU-13/E coupling assembly is for use with a 4-inch hose.