Brush Mate Fluid is for use with the brush mate trade 20 simply take out your empty bottle and replace it with a full one. This fluid will keep your wet paint brushes/ rollers wet and ready to use for months (when used in conjunction with the Brush Mate Trade 20 system).  The clear liquid evaporates very slowly, producing a powerful heavier-than-air solvent vapour that fills the container. This vapour prevents the solvent evaporation and film formation of oil-based or alkyd paints and varnishes, allowing you to store wet paint brushes used with these coatings for many months.