The MAC 77 series solenoid valve is a 3-way balanced POP (pilot lift valve) pilot valve operated by a small direct acting four-way solenoid valve - secondary for air valve manufacturing. 4 Guide valves mean low operating pressure - no piston - and little resistance. The balanced pilot design means that the shift force is consistently high and response time is repeatable regardless of inlet pressure fluctuations. Information about certifications (e.g. UL, CSA, RoHS, CE)