I watched some review on youtube.. you can see how this is a great idea but doesn't work that well in real life. It can kill fly at best.. but it won't kill bugs like spider, let alone cockroach etc. Oh and be prepared to have the bug bounces off the wall and on to you or somewhere far where you couldn't find it again.
sanibuy...it definitely kills spiders and cockroaches, you just have to go closer than 3 feet. It explodes crickets, and it's pretty disgusting (but fun).