This natural heather pullover Irish Knit Sweater looks great on any dog, and is quite comfortable. Machine washable sweaters are made of soft, acrylic that will keep dogs toasty-warm, and features a chunky turtleneck and ribbed knit at the bottom for a great fit. Please use the following guide to determine the correct size for your dog. Measure the length of your pet's back from the base of neck to the base of tail. If the measurement is between sizes or if your pet has a stouter build, is overweight or has a deep chest, we recommend selecting the next size up for a proper fit. If your dog is long-backed, like a Dachshund, a smaller size is recommended. Extra Small fits up to 8" Small fits 8"-12" Medium fits 12"-16" Large fits 16"-20" Extra Large fits 20"-24"