All of these martingale collars are made with steel hardware, the D-ring is welded to prevent separation. The inner material is seat belt strapping with a breaking strength of 3000 lbs. 100% nylon thread rated for outdoor use so if your dog gets it wet the strength is still there.  Machine wash in warm water and dry flat.

Medium martingale collars fit a neck size from 15-19 inches and are available in 1.5 inch or 2 inch Martingales. Most Greyhounds are this size.

Large martingale collars fit a neck size from 18-25 inches and are available in 1.5 or 2 inch Martingales. Most other dogs are this size due to their head being bigger than their neck.