HopGuard® 3 is the new and improved generation! ; HopGuard® 3 Properties: Naturally derived from hops, No chemical residues, Safe during honey flow, Easy & effective, Safe on bees - deadly on Varroa mites, Easy - AND SAFE - to use ; HopGuard® 3 Usage: The daytime temperatures should be above 50°F (10°C), Simply add HopGuard® 3 to hives at the rate of two strips per 10 frames of bees, Strips should be hung between brood frames, Refere to package label for full instructions.