This is from an organization that is non profit. They are trying to get as many of these out as possible. I would read the web site and make sure the zapper is positive offset, and at least 9V. If you are low on money and it's an emergency, I would get this one. The best zapper is the homemade one. I have the zapper deluxe- $200.00- and it is trash. I am going to make another zapper soon.