PIC Mosquito Repellent Coils contain a proven formula of Pyrethrum. Each coil lasts up to 5 to 7 hours. Comes with reusable metal stands. Mosquito Coils help 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 and see packaging for additional instructions for proper use. Coils repel mosquitoes that may transmit zika virus and are effective when positioned every 10 feet. Each coil burns for 5-7 hours and is best used outside on patios and porches. For outdoor use only. Use the enclosed metal holder for positioning the coil above the surface of your patio table or wherever you place the coil for repelling mosquitoes. Note the direction of any breeze or wind when placing the coil around outdoor activity.