The Dog Helios 'Ice-Breaker' Extendable Hooded Dog Coat is inner lined with Heat Reflection Technology, a specially developed Lightweight inner barrier that Reflects back Natural Body heat back into the body. The Ice-Breaker Dog Jacket also features a dual extendable hood design with dual jawstrings that extend and cover a larger portion of the facial area to prevent colder air from entering. The sleeves offer elastic stitching that conform to proper leg girths with a waist buckle that adjusts to various dog chest sizes to further seal out the outdoor frigid air temperatures while offering a more premium and comfortable fit. The Exterior shell is Waterproof Coated and Features Reflective Tubing and Printing throughout the body. Available in Multiple Sizes and Colors. General Sizing Guide: From Back of Neck to Tail area ("In" Inches) 8" : EXTRA SMALL 10-12": SMALL 14-16": MEDIUM 18-20": LARGE 22-24": EXTRA LARGE. Sizing Specifications: (In Inches). XS: 8.3" Length, 17.7" Chest Girth, 12.2" Neck Girth SM: 11.8" Length, 21.7" Chest Girth, 13.7" Neck Girth MD: 15" Length, 24.4" Chest Girth, 15.8" Neck Girth LG: 18.9" Length, 29.9" Chest Girth, 16.9" Neck Girth XL: 22.8" Length, 34.7" Chest Girth, 18.9" Neck Girth