I have used a lot of them, absolutely deadly on coyotes. There are different kinds of locks on the snares and I have released several dogs from the relaxing type locks. Most domestic dogs will figure out real quick if they quit pulling they don't get choked and you find them there in the snare waiting to be let go.I use these types when the landowners have dogs that roam. No dogs around I like the Amberg lock, it won't relax and you will have a dead coyote or fox. With the relaxing lock most of them will still be alive as they figure out not to pull as well. You will get some chew outs with a relaxing lock though.