Product Features Rechargeable Refills create a 20-foot zone of protection against mosquitoes their largest zone yet. This cartridge is compatible with all Thermacell rechargeable repellers. Each scent-free refills provide 36 hours of on-demand, continuous mosquito protection. Portable and TSA-compliant. Thermacell rechargeable devices are powered by a lithium-ion battery. Heat activates the repellent to provide maximum protection in 15 minutes. Portable and TSA-compliant. Repel mosquitoes without DEET sprays or lotions on your skin. No smoke, flames, or strong scents like citronella. Independently tested and EPA-reviewed for safety & effectiveness. People and pet friendly. Backed by the Thermacell Guarantee. See packaging for details. Includes Two 36-hour repellent refills.