Warmth, protection & style in one jacket, Why you'll love the Everest Explorer Vest A rugged water-resistant shell to keep your dog protected from the elements Soft fleece lining & faux-down insulation for ultimate warmth Faux-fur trim to add style Dual velcro closure for your pup BACK LENGTH Measure from the base of your dogs neck (right below where their collar would sit) all the way to just above the top of their tail. CHEST GIRTH Measure around the largest part of your dogs chest, just behind their forelimbs. Size Back Length Chest Girth 8 8" Up To 15.75" 10 10" Up To 17.75" 12 12" Up To 21" 14 14" Up To 23" 14+ 14+" Up To 25.5" 16 16" Up To 26" 18 18" Up To 27" 20 20" Up To 28.5" 20+ 20+" Up To 30.5" 22 22" Up To 30" 24 24" Up To 31.5" 26 26" Up To 34" 28 28" Up To 37"