I have bought and returned 1/2 and 1 acre Stinger bug zappers from Costco 4 times now in the past 3 years. Thank God I was buying from Costco as Stinger products are worthless. Light attracts them but zappers don't work. Some worked for a week and others didn't zap at all. I don't know why Costco carries such a terrible product. I kept thinking, maybe these were a bad batch and I will finally get a good product. Not so, do not buy these products.