In this paper. we consider a special class of optimization problems which contains infinitely many inequality constraints and finitely many complementarity constraints known as the semi-infinite mathematical programming problem with equilibrium constraints (SIMPEC). We propose Lagrange type dual model for the SIMPEC and obtain their duality results using convexity assumptions. Further. http://www.ngetikin.com/special-pick-MVP4-Moisture-Vapor-Protection-Anti-Fracture-and-Noise-Reduction-Membrane-special-save/