Up Country Martingale collars are a gentle way to have control over your dog. Perfect for dogs that pull or easily slip out of their collars. Martingales create an even tension around the neck avoiding neck and throat injuries. Please note: Martingale collars should never be left on dogs without supervision. Sizing: Small (5/8” Wide) - 12-17.5”, Medium (1” Wide) - 12.5 - 20”, Large (1” Wide) - 13.5 - 22.5”, and Extra Large (1” Wide) - 12 - 25”.