I once had a rat problem, the bastard was a clever one, first I opted for a non harmful trap I didn't want to hurt and kill it, that failed............. he outsmarted me, then I went for a trap with teeth, again that bastard outsmarted me, so finally I had to go for the rat killers ............. the previous two were expensive and useless but the last one was cheap and effective. Now I don't have to worry that bastard ate one of it and went breathing in some open air out of my house, most probably dead not to bother anyone else again.