Pig made material selection positioning bar leak composite plates, especially the characteristics of the composite material, is because the formula is reasonable, the craft, easy to forming and molding shrinkage rate is low, the size, has the good electrical insulation, flame retardancy and mechanical strength, low coefficient of thermal conductivity coefficient, no impact and noise, friction resistance, corrosion resistance, high and low temperature in winter is warm effect (warm in winter and cool in summer).