This portable set features Welch Allyn's finest diagnostic instruments. The 11730 3.5V Coaxial Ophthalmoscope Head features precision optic with 68 lenses in single-diopter steps (+38 to -30). Halogen lamp illumination insures true tissue color and a Polarizing filter virtually eliminates corneal reflection. The Welch Allyn 3.5V Operating Otoscope Head with Specula (21700) has an open system, rotatable lens and speculum for convenient procedures. It uses a Halogen HPX lamp that provides 30% more light output for true tissue color and consistent, long-lasting illumination. The fiber optic illumination produces cool light. It has a rotatable lens and speculum. 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.