Thermacell PATIO SHIELD MOSQUITO PROTECTION alleviates the annoyance from mosquitoes by repelling and killing mosquitoes and reducing the number of bites in an area as large as an average-size deck or patio (up to 4.5 metres from the product) for up to four hours. This product is portable and can be taken anywhere you expect annoying mosquitoes to be a problem. For use in backyards and other outdoor recreational areas such as patios and decks.