Before going into production, substantial numbers of 64200 prototype production units were subjected to field service for over 60 days at locations around the world. The nozzles were returned for evaluation by Carter engineering to effect changes to resolve conditions noted in the field. In its military version, 64201, it was qualified to MIL-N-5877 and field trials have been conducted by the Navy. Personal preferences, although not problematic, were taken into account when the nozzle was put into production.
