The Skeeter Screen Patio Egg Mosquito Deterrent Diffuser is an easy, safe & effective way to help deter mosquitoes and other biting insects from your patio and other outdoor living areas. The deet free Scents of Nature formula is derived from natural essential oils. The Patio Egg's porous nature allows the fragrance to migrate up the sides and to diffuse into your surroundings. Expect the egg to darken in color as the oil is absorbed. The pleasant floral scent will hatch within 24 hours and will be effective continuously 24 hours a day. The Patio Egg may be suspended by its nest of netting or placed upon a flat surface by removing the netting. Box includes 1 patio egg and netting, measuring cup, and 4 fl oz of Skeeter Screen oil. Refill oil bottles are available for purchase separately.