Formic Pro is an all natural, raw material made from formic acid. It kills mites under the brood cap. It is a biodegradable, ready to use product and is residue free. There is no known resistance. Use in spring and fall for mite control. It doesn’t require temperature controlled storage and kills immature and adult varroa mites. Also controls tracheal mites.2 treatment options:-2 strips on for 14 days OR-1 strip for 10 days followed by a second strip for 10 days-Place on hives when outdoor daytime temperatures are between 50 and 85 degrees F You are buying a new, unopened package of 4 strips (2 doses) of Formic Pro. At Dogwood Ridge Bees, we are Experienced Beekeepers and will gladly answer your questions.We make our own line of woodenware: 8 & 10 frame Hive Bodies (Deep, Medium, & Shallow), Solid & Screened Bottom Boards, Inner Covers, Wooden Lids with Metal Covers, Screened Inner Covers, Top Entrances, Migratory Covers, Nuc Kits and accessories, Feeders, and more.We carry a complete line of beekeeping supplies (protective wear, tools, extractors, bottles, hive health, books, etc.) to meet all your beekeeping needs.