Raid Max Fly Mosquito Protection Plug-In effectively controls flies & mosquitos for 24 hours a day (if used for 10 days) or 8 hours a day (if used for 30 days & nights). It is an electric device that combines a compact diffuser with a compressed sand refill containing an active ingredient to control flies & mosquitoes. The refill is enclosed in plastic allowing you to avoid touching the active ingredient. A light tells you the product is switched-on. After 240 hours of use, when the liquid use-up indicator has dried-up, substitute the refill to renew fly & mosquito protection. - Compact diffuser Light. - Compressed sand containing the substance to control flies & mosquitoes. - Use-up indicator. More than 200 hours control (Up to 10 days x 24 hours control). No Leak Sand-Infused Technology (The active ingredient is embedded in the sand so that the active doesn't leak).