March 17, 2016 Andrew Isaacs Solenoid Valves HS4D Two Step Solenoid Valve March 17, 2016 Andrew Isaacs Solenoid Valves Hansen Technologies introduces the HS4D Two Step Solenoid Valve. The HS4D is based on the same strength, reliability, design principles and craftsmanship as the standard Hansen HS4A Solenoid Valve—with added versatility.
