Training Collars were Black Dog's first ever product. They were designed for training without the harshness and pain of a chain choker. Nowadays, the training collar is generally used more as a security collar because of the non-slip security of a martingale design - the design helps prevent dogs slipping out of their collar. Careful consideration to design of the collar, components and choice of materials in relation to the size of dog, has enabled Black Dog Wear to produce a highly effective Training Collar that is robust and looks great. Features: Adjustable - to exactly and comfortably fit a dog's neck, and can be adjusted as your dog grows. Extremely easy and safe to use. Simple to fit. Unique "Designer Dog Wear" appeal backed with Black Dog's quality guarantee. Will not over tighten on a dog's neck - the cause of nasty K-9 throat & neck injuries. Will not cut, mark or remove a dog's coat. For extremely strong, pulling dogs, a totally secure Heavy Duty Training Collar is available. See separate entry. Small: 25cm to 35cm. 20mm wide. Medium: 32cm to 41cm. 20mm wide.Large: 40cm to 54cm. 20mm wide. XLarge: 53cm to 79cm. 20mm wide.