Have bought a number of these before. and these are our favorite kind.  Even though the bugs still have to be blown out or gently tapped out, they don't stick to the electric grid like other bug zappers we've had.  Zillions of bugs, mostly mosquitoes, fall out onto the ground underneath.  Like the other zappers, these only seem to work for a couple of years, but they're worth their weight in gold for controlling mosquitoes.