It doesn't kill anything. Supposedly, it just makes an annoying sound for pests, assuming that there are frequencies inaudible to the human ear, but very bothersome for lesser creatures.
I have a similar product and I can't say if it worked or not. I can't see inside my walls to know if bugs are being repelled. I still see the occasional bugs, but I don't see them "repelled" by the product.
What I do know that works is boric acid that you can get at Home Depot, a white powder that you would put around baseboards and other hidden areas. It is messy, though.