The Dog Helios 'Ice-Breaker' Extendable Hooded Dog Coat is inner linned with Heat Reflection Technology, a specially developed Lightweight inner barrier that Reflects back Natural Body heat back into the body. These heat reflective dog coats also feature a dual extendable hood design with dual jaw-strings 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. Our hooded dog jacket is 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