Features: Triple Security: velcro closure, quality buckle clip and double D-rings for secure leash attachment. Adjustable design fits better than traditional harnesses!Breathable mesh that keeps your dog comfortable and is perfect for all types of weatherAvailable in an array of colors and sizes ensuring you find the perfect fit. HASSLE FREE GUARANTEE! Free exchanges if it doesn't fit your dog. BUY WITH PEACE OF MIND TODAY! Size Chart: X-Small: Fits 12 - 13" chest, 8" neck; Small: Fits 14 - 16" chest, 9.5" neck; Medium: Fits 16 - 18" chest, 11" neck; Large: Fits 18 - 21" chest, 13" neck; X-LARGE: Fits 20"-23" chest, 18"-22" neck