flea spray aerosol + igr treats 2625 sq. ft. qick kill long residual ultracide not for sale to: california basf ultracide is the best flea control aerosol designed for indoor use. ultracide provides an immediate kill of fleas, and keeps eggs and larvae from developing further for up to 7 months. ultracide has practically no odor and a very long residual. each can can treat up to 2600 sq. ft!