The Thermacell ER55C Rechargeable Mosquito Repellent Unit with a 12-hour refill is a reliable solution for keeping mosquitoes at bay during outdoor activities. With an EPA registration number of 71910-11, this odorless unit provides 12 hours of protection indoors or outdoors. Its refillable feature ensures long-lasting use, making it a convenient and effective option for campers, hikers, and other outdoor enthusiasts looking to survive the summer bug-free.