American Educational Longitudinal Wave Demonstration, 18" Length x 6" Width x 11" HeightGreat for demonstrating difficult to explain resonant waves, such as propagation, reflection, and interference Two cast metal supports, 15 1 4" tall by 9 1 2" deep, are extended by connector rods making a frame A white cotton cloth backing is stretched between the frames to help make the demonstration visible A 3" diameter spring stretches between the frame ends that can be set up to 110cm apart Measures 18" length by 6" width by 11" height Great for