Country Brook Design | 1/2 Inch Martingale Dog Collar - American Pride Collection Collar fits (15IN - 21IN) neck. There are no standard sizes for dog collars. Please be sure to measure your dog's neck for correct size. Measure around your dog's neck (with string or tape measure) snugly where you want the collar to lay. If you have any questions or problems with sizes please give us a call before ordering. Breed Recommendation: Greyhound, French Bulldog, or Collie Traditional martingale collar has no buckle for superior strength. Made in U.S.A. Made with top quality hardware