The Dog Helios 'Vortex' Full Bodied Waterproof Windbreaker Dog Jacket features an Armor-like design. This dog coat features a Nylon-Polyester Blended outershell that is Waterproof coated, Tear-Proof and Medium-weight that is Heavy enough for the Winter and Light enough for the Spring. Lightly reversed with Anti-Static Polar Fleece. This Dog Coat features Reflective Tubing and traingular Reflective Printing across the backside. Fully adjustable around the chest area for a glove-like fit. Each sleeve features Hook-and-Loop enclosures for a perfectly tailored fit and to prevent wind or cold-air from entering. Available in Multiple 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