This is a convertible version of Welch Allyn's universal rechargeable handle to power all Welch Allyn 3.5V instrument heads. A convenient built-in charger allows you to plug the handle into any conventional wall outlet for overnight recharging. 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. Also, the convertible handle is very useful when working overseas or in areas where it's difficult to find electricity.The handle is well-balanced and rests comfortably in the hand. Its weight is evenly distributed end to end. It has an adjustable rheostat control and a free-floating reserve setting that allows optimal intensity and battery life. Its smooth, non-abrasive knurled finish ensures a no-slip grip. Its chrome-plated brass handles provide durable, long-life construction. It has a safety switch to prevent accidental draining of the battery. Metal head connectors for durability.