SIZING GUIDE S/M Length: 13-20 (5/8 wide) L/xL Length: 19-30 (1 wide) These collars are made of high quality polyester webbing, plastic buckle, & a heavy duty D-ring to hook onto. They are adjustable to the the size ranges listed above. Collars are handmade in New Hampshire. Oahu Red Hibiscus Dog Collar