For the backyard and beyond, the Thermacell E-series is easy to use and provides hours of scent-free, mess-free mosquito defense. Our largest area repellent zone available, the E55 provides a 20-foot (6 m) zone of advanced mosquito repellent. Features a 5.5-hour battery – can charge while operating to extend run time. 12 hours of mosquito repellent included. Audio cues and LEDs let you know you’re covered and how much battery life remains. This 36-Hour Refill is compatible with Thermacell Rechargeable repellers – Radius and E55 (does not work with fuel-powered repellers). Keep mosquitoes away with the simple push of a button.