With a foam-trapping action, the spray quickly kills wasps and hornets - including yellow jackets - on contact. It has a powerful jet spray that can reach up to 25 feet. The water-based foam will kill insects returning to the nest for a thorough and optimal extermination performance. It's safe on most ornamental plants and shrubs and won't stain most home siding and asphalt shingles depending on the condition and cleanliness.  The foam contains a 0.5% concentration of its active ingredient, Permethrin, an insecticide that is a powerful killing agent on insects.