The MAC 27 Series is a 4-way P.O.P. (Pilot Operated Poppet) designed solenoid air valve. The 4-way pilot means a low minimum operating pressure - no pistons and minimal resistance to shifting. The balanced design in the pilot means shifting forces are consistently high and response times are repeatable regardless of inlet pressure fluctuations. For information regarding certifications (such as UL, CSA, RoHS and CE) please visit the Get Support pages on our website.