Harris Roach Gallon Spray uses a water-based, odorless formula kills roaches after spray dries thoroughly. This crack and crevice and contact spray keeps killing German cockroaches for up to one year. We recommend using this product with Harris Famous Roach tablets to most effectively control infestations and prevent roaches from returning. Application Apply as spot and crack and crevice treatment to areas where roaches crawl and hide, especially in hidden areas around sinks and storage areas, behind baseboards, around windows and doors, and behind and under refrigerators, cabinets and sinks. Always read and follow label directions before and during use.