This portable set features Welch Allyn's finest diagnostic instruments. 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 MacroView Otoscope (23820) uses Halogen HPX lamp and fiber optics for cool light with no reflections, no obstruction. It comes with a built-in throat illuminator/penlight and a wide-angle viewing lens for instrumentation under magnification. The Welch Allyn Lithium-Ion (Smart) Handle (71900) is just half the weight of current 3.5v handles. It averages 120 minutes of on time between charging. It has the smallest diameter of any 3.5v power handle on the market. The textured handle is made of sturdy resin. It comes with a low-battery indicator and lithium-ion battery technology that has no "memory" effect. It has a soft-grip rheostat intensity control, and AC charging module with retractable prongs that is easily removable from the handle.