The collar has a 100% nylon webbing core surrounded with a cotton fabric re-enforced with lining to improve strength. Collars are made with about 6-10 inches of adjustment (circumference). Measuring your dog: Martingale Collar: Be sure to measure the circumference of your dog's head at the largest part. Clip Collar: Be sure to measure the circumference of your dog's neck Length Size Chart (based on your dog's head/neck) XS: 6-10 in Small: 8-14 in Medium: 12-18 in Large: 16-22 in XL: 20-26 in Width Size Chart Small / Medium: 1.0 in Large: 1.5 in XL: 2.0 in Please allow for variations from the photos as no two collars are exactly alike. Pattern placement of fabric may vary. Care Instructions: Please wash collars with like colours and hang to dry. Do not iron. Do not bleach. Do not put in dryer.