Just One Bite EX Bait Stations contain the active ingredient bromethalin, which causes a "stop-feed" action. Most mice will stop feeding after consuming a single lethal dose. At that point, it usually takes up to two to five days from the time of ingestion for the mice to die. Each of the disposable, moisture resistant bait stations is pre-loaded with a single 0.5 oz block of Just One Bite EX bait for mice. This product is effective against mice that have become resistant to anti-coagulant baits.