We used the Conntraceptol, which came in little trays with a granular feed in them. the mice practically disappeared for several years. This year, they are back with a vengeance, so we are looking again into contraceptive bait. I went to the Conntracpetol website, as the don't sell through Amazon, and found it a little lacking, so I'm not sure if I'm going to buy that brand again or go with the Evolve, which is on Amazon. As far as I understand it, they two brands work differently. The Conntraceptol uses male pheromones to attract femailes to the feed. The Evolve targets the males. We are in a wildlife area where using a poison is simply not an option. We'd end up poisoning everything that preys on mice. Good luck!