The Collar For The Adventurous Our collars are waterproof, stink-proof, highly-durable, and feature vibrant colors to help you stand out! Our Chunky Mutt series is made with extra thick 1.5" webbing, perfect for pups who like a little more support. Like all of our gear, this series is made with solid brass hardware. Collar Sizing Guide: Medium: 11-16 inches Large: 15-20 inches XL: 20-24 inches Please be sure to double check your pup's collar size! Ensuring size is the responsibility of the buyer and we do not accept returns or exchanges on products where the wrong size is selected. It's always best to measure twice just to be sure!