Dogzilla Dinosaur Costume is great for parties, photo opportunities, or get togethers. Unleash your very own Dogzilla this Halloween and make your pet the life of the party. Dogzilla Dinosaur Costume is a one piece suit. It features an adjustable, elastic Velcro tabs, making it easy to put on and take off. Sizing Guide: Measure length of pet’s back from the base of the neck to the base of the tail. If the measurement is between sizes or pet has a stouter build, we recommend selecting the next size up for a proper fit. SMALL 8″-12″: Silky Terrier, Boston Terrier, Maltese, Jack Russell Terrier, Pug. MEDIUM 12″-16″: Cocker Spaniel, Scottish Terrier, Bichon Frise, Beagle, Corgi. LARGE 16″-20″: Springer Spaniel, Brittany Spaniel, Border Collie, Dalmatian.