Protect outdoor adventures from mosquitoes using Thermacell Radius Zone Mosquito Repellent. Offering 36-hour protection from harmful mosquitoes, Radius Refill cartridges are compatible with the rechargeable Radius Zone Mosquito Repellers and have been evaluated by the EPA for safety and effectiveness. To use, simply replace empty refill with a fresh one. The fully-sealed, no spray, mess-free refill offers mosquito protection within a 15-foot area. With the Thermacell scent-free, DEET-free and invisible repellent system, users are blissfully unaware that Radius is working hard to deter mosquitoes until going outside the zone and are bitten. The refill is also spill-proof, featuring a travel-friendly design, perfectly suited for the next backyard party, neighborhood BBQ, evening on the patio with friends or family campout.