Cube, Individual cubes for density experiments, Available in eight different materials: acrylic, aluminum, brass, copper, nylon, polypropylene, PVC, and steel, Each material is represented by a 1/2inch, 1inch and 11/2inch cube
ultrasonic Probe, Dimensions: 65 mm X 27 mm Dia, For Use With ultrasonic Echoscope, Includes A 16-mm Piezo-Ceramic Disc In A Die-Cast Metal Case And A 1-M Long Cable With A Frequency-Coded Snap-In Plug, Equipment Is Adapted To Sound In Water/Acrylic, 4 Mhz.