Yea a 2 wire solenoid.. the 1 that comes with the spec1 is a medium size black box that says greddy on it. The replacement solenoids for the spec2 n typeS will plug up but wont work b/c my head unit doesnt have a vacuum nipple like 8th the newer controllers.. the pressure is held in the solenoid box itself.. my only hope is if dr emmino n dr Brantley can fix mine.. if not ima jus upgrade to mayb a aem truboost or mayn just a typeS to keep it simple