ISO-A 3/4" NPT hydraulic quick coupler plug with ball. ISO-A type hydraulic quick coupler with ball plug and 3/4" NPT female thread. It is designed to allow quick and clean disconnection and connection of hydraulic systems, and to protect them from the ingress of contaminants, which could cause damage or malfunction. Parameters: Standard: ISO-A Thread: 3/4" NPT internal C: 53.5 mm CH: 34 mm