The Yellow Chewy Tube is smooth and used used with a smaller jaw, typically infants and children up to 2 years old and individuals who cannot open the jaw very wide. It features a hollow, narrow stem of 3/8″ outside diameter (OD). Yellow, smooth, small-stemmed, T-shaped, tubular For chewing and biting skills, TMJ stimulation, eliminating teeth grinding… Integrated in the Bite Tube Set and in the “Jaw Book” Reusable, durable and easy to clean