Double Convex round Lens, Material: Glass, designed for physics and educational uses, Because of their educational use design, there may be minor imperfections that do not affect physical function, for educational uses, Size: 250mm focal length, 50mm diameter and 4mm thick
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.