Good Knight Gold Flash Mosquito Repellent Refill can be used in all electronic mosquito repellent machines but works best when used with Good Knight Gold Flash machine. It protects you and your family Good Knight Gold Flash protects you from all kinds of mosquitoes. It has an advanced formula that releases visible Gold Flash vapours for the first 30 minutes. It has an intelligent heater system that automatically switches to Flash mode every 4 hours for 30 minutes and then goes back to normal mode. So, switch to Gold Flash Refill and keep your house mosquito-free all day.