First Class Travel for Pets! On the Go is a versatile travel pack that can be used three ways on the back as a pack, over the shoulder, or around the waist. On the Go is built with quality materials to make critter travel safe as well as fun and cozy. On the Go features a built-in water holder that perfectly fits a 4 oz. Critter Canteen (Item #61950) or a 4 oz. Flat-Bac Water Bottle (Item #61930).13"L x 8"W x 9"HPlease note: Color specification is unavailable on this item