PIC® Mosquito Repelling Coils helps to repel mosquitoes in confined areas outdoors. It is useful in places where there is little or no breeze such as patios and porches. Do not use indoors. Repels mosquitoes that may transmit Zika virus. Each Coil Burns For 5-7 Hours Outdoors Place One Coil Every 10 Feet Use On Patios and Porches PIC®- Dependable Insect and Rodent Control Since 1953