Malibu Mosquito Inhibitor Refills contain 2 refill cartridges and work in any Malibu Mosquito Inhibitor model. These refills do what others can't: they block the mosquito's ability to track your scent by using the patented chemical Linalool that was developed in cooperation with the USDA. Linalool was found to be twice as effective as DEET and many times better than Citronella oil at preventing mosquitoes from homing in on human scent, blocking mosquitos up to 100 feet.Features Include:Blocks mosquito's ability to track human scent Each Refill lasts up to 2 weeksProtects up to 100 square feet 2 refills includedWorks with any Malibu Mosquito Inhibitor model