Hello friends today I am going to share my opinion about good knight advance action.If you buy the good knight machine with refill then it will cheap at cost otherwise its refill is little costly.If I talk about its effectiveness so nowadays it is not working very well.When I turn on normal mode then I realize that it is not working on mosquitoes, Mosquitoes are flying near the machine but when I turn on the active mode but still it is not working.Before buying these type of products read this review carefully I hope it will help you.