Topic summary
Electric razor

Extracted from the Wikipedia article Electric shaver.
Battery-powered electric razors
In the late 1940s, the first battery-powered electric razors entered the market. In 1960, Remington introduced the first rechargeable battery-powered electric razor. Battery-operated electric razors have been available using rechargeable batteries sealed inside the razor's case, previously nickel cadmium or, more recently, nickel metal hydride. Some modern shavers use Lithium-ion batteries (which do not suffer from memory effect). Sealed battery shavers either have built-in or external charging devices. Some shavers may be designed to plug directly into a wall outlet with a swing-out or pop-up plug, or have a detachable AC cord. Other shavers have recharging base units that plug into an AC outlet and provide DC power at the base contacts (eliminating the need for the AC-to-DC converter to be inside the razor, reducing the risk of electric shock). In order to prevent any risk of electric shock, shavers designed for wet use usually do not allow corded use and will not turn on until the charging adapter cord is disconnected or the shaver is removed from the charging base.