A hybrid type dog collar where most of the collar is of flat material like leather or nylon but the top has 3 metal rings which should form two loops, one of which is for the dogs neck and the other tightens and loosens when necessary.
Pro: This collar was created for slim neck dogs like Greyhounds and Whippets to prevent their heads from slipping out. Eventually many dog owners started using them to outsmart their escape artists.
Con: Most humans find it difficult to use this collar effectively for training.