7 lb, #549, sub floor patch & skim coat feather finish, prep & prepare, easily fills in ridges, gouges, depressions & seams all most any sub floor, use over any surface & dries in 15 minutes, installs from feather edge to a depth, easy to mix by adding water, no primer or additives needed, Portland cement based, will not stain or mildew, exceptional bond to concrete, wood, terrazzo & ceramic tile, coverage at 7 lb unit covers up to 24 sqft at 1/8", when skimming over concrete, coverage is 70-100 sqft & over plywood, up to 198 sqft can be achieved.