Footwear Waterproofing (Concentrate) Dry Guy Footwear Waterproofing (Concentrate) Superior BREATHABLE waterproofing concentrate specifically formulated for Footwear. Dry Guy is a water based waterproofing liquid concentrate Dry Guy is totally safe for the environment Dry Guy lets your boots breathe while protecting against moisture, mould and stains! COVERAGE AREA 390 ml. /13.18 oz. covers 240-300 square feet per bottle.