... fasteners . 5,SpaLux Premium Marine Grade Vinyl,that has built in resistance to chlorine ,bromine ,mildew &UV. 6,4 layer,quadruple ... polyester thread . 8,Customized Perimeter skirt that helps keep heat in and dirt out ,while adding to the appearance of your ... ,bromine and mildew .Optional reflective material available . 12,Weep holes in the bottom of the cover allow condensated water to drain .