About this product range:~ 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 & Cozy. On The Go Features A Built-In Water Holder That Perfectly Fits A 4 Oz. Critter Canteen Or A 4 Oz. Flat-Bac Water Bottle.