LESYPET Cold Weather Vest For Medium and Large Dogs With Safe Guard Zipper Closure Windproof SIZE 18: 3XL-Back:19.5",Chest:26",Neck:18". More Features: Machine washable, water resistant outer layer, durable, fine in detail , wind-proof. Occasions: Outdoor or indoor activitives. Perfect for sports, daily wear, photo. O-Ring attached on the back. Tips: To better fit your dog, please do measure the size of your dog and compare to the size chart or consult with us before placing order.