Easy to use. Simple to clean. Made with a super strong flex-poly strap, the all-weather Collar is comfortable and functional. It's also dirt and odor-resistant. XS: Neck: 7-10. Strap width: 1/2 S: Neck: 8-12 Strap width: 3/4 M: 12-15 Neck: 3/4 Strap width: L: Neck: 15-18 Strap width: 1 XL: Neck: 18-23 Strap width: 1