The one and only corrugated plastic tubes that make an amazing, addicting sound when pulled open and pushed together. 7 inch long, vibrantly colored pipes expand to 28" when fully expanded. Pipes can be linked together and bent to form twisted designs and marble mazes (sorry-no marble included). Great for developing hand, finger and arm strength, hand stability, bilateral coordination, motor planning and visual and auditory attending. 12 pipes to a set.