Lens met een veranderbaar brandpunt. Met de spuit wordt een grotere of minder grote hoeveelheid water in de flexibele lens gestopt. Use the included syringe to adjust the amount of water in the clear flexible membrane. Perfect for demonstrations involving focal length of lens changes relative to to the curvature of the membrane. For use with either the Basic Optics System (OS-8515C) or the Human Eye Model (OS-8477). Includes: -Adjustable lens with flexible membrane (2) -Silicone tubing - 1 ft -10 mL Syringe -Instructions The Adjustable Focal Length Lens (OS-8494) is an accessory for the: -Human Eye Model (OS-8477) -Basic Optics System (OS-8515C)