The Sport toys are constructed with three layers of material - two layers of industrial grade nylon and one layer of soft fleece all sewn together (think quilting!) with two layers of cross stitching as well as two layers of linear stitching to prevent separation. After being sewn together an additiona piece of black nylon trim is added to cover the four rows of stitching. This ensures toughness while remaining soft and flexible to protect teeth and gums. Internal squeakers are sewn into individual pouches within the toys. Each toy is washable (air dry please!) and they float!