3M DRY GUIDE COAT CARTRIDGE - Dry powder used to highlight surface imperfections such as pinholes and deep scratches in primer prior to finishing with abrasives. Requires no masking and there is no dry time involved. Can be used on marine fillers, primers, paints and gelcoat. Can be used for both wet and dry sanding. Contains no solvents. Cartridge is 50 grams. Applicator is sold separately.