The Belvoir Rug Company Dog Onesie is an all in one dog protection cover that is perfect for keeping your dog clean whilst out for a walk or for dogs that shed their coat in and around the house. The product utilises Xtra-Life lycra technology which gives the Dog Onesie extended life and extra durability. Sizes - Extra Small: Small Chihuahua. Small: Long Hair Chihuahua/Small Terrier. Medium: Small Spaniel. Large: Cocker Spaniel. Extra Large: Labrador. 2 x Extra Large: Large Labrador.