The 18320c set includes an ophthalmoscope, retinoscope, rechargeable handle and hard case. The Coaxial Ophthalmoscope (11720) uses a Halogen HPX lamp that provides 30% more light output for true tissue color and consistent, long-lasting illumination. It has 28 lenses from -25 to diopters for better resolution. The coaxial optical system produces a shadow-free spot and easier entry into undilated pupils. The crossed-linear polarizing filter reduces corneal reflection. The red-free filter may be used with any aperture. It has 18 possible aperture combinations for greater versatility. The Streak Retinoscope (18200) enables easier and quicker refractions with a crossed linear polarizing filter that eliminates bothersome glare from trial lenses. Sealed optics keep the lenses cleaner. The 71000C universal rechargeable handle accepts all Welch Allyn 3.5v instrument heads. Its chrome-plated brass handle rests comfortably in the hand. It comes with an adjustable rheostat control; smooth, knurled finish; and safety switch to prevent accidental battery drainage. It can be recharged by plugging directly into a wall outlet. The 71000C model also includes a battery converter accessory that allows the handle be powered by C-cell batteries, a handy feature if you're on call or have forgotten to charge the battery.