Since power supplies in different countries put out differing currents than those in the USA, various adapters are needed to run electronic devices safely so that they will not be damaged.
These adapters can be used to plug into all kinds of various electronic devices to ensure their safety while being used.
The United States and most of the western world uses an electrical system that uses 110-120 volts. Much of the rest of the world uses a 200-240 volt system, some countries uses alternating current and some use direct current. The bottom line is that unless you allow for some kind of adapter to change the current to the one your device is used to using, you may well destroy your device.
The World Travel Adapter from Apple is an outlet adapter kit that is designed to allow your Apple devices to work overseas in countries where the power supply has a different voltage. You can use the kit to work with your iPad, iPhone, your MacBook and MacBook Pro, iBook, PowerBook and AirPort Express.
If you are using a device such as the iPhone 5, the iPad with Retina display, or an iPad mini, all which use a Lightening connector, you will need a Lightening to USB special cable, which can be purchased separately.
The World Travel Adapter kit has plugs that work in the United Kingdom, Continental Europe, Australia, North America, Japan, China, Korea and Hong Kong.
The devices listed here have auto-sensing power supplies and auto switching capabilities. All that needs to be done is to plug in the right plug adapter to the device in order to have it work properly in other countries that are supported.
Even though it is stated that the electrical power is within the supported range for your device, you should be sure that the quality of the power where you are located meets specifications. Power surges, brown outs and electrical spikes can seriously damage electronic equipment.
Other world travel adapters are used for purposes other than just for electronic devices. Items such as electric shavers, batteries, radios, CD players, digital cameras, mobile phones, various kitchen appliances, and other electrical items.
There are many different brands of travel adapters on the market, and technically, an adapter simply adapts the travel device to the plug configuration, but does not change the voltage. In order to change the voltage to its proper level, a transformer is needed. It is difficult to know exactly what a certain device will do, simply because an adapter is called the same thing, but it can do two different jobs.
Also, depending upon the part of the world you are traveling to, different parts of the world require different specifications of travel adapters. The most traveled areas from the United States such as Europe, Canada, Mexico, and South America have accessibility for adapters. India, China, Middle Eastern countries and others may take more research and care in purchasing the types of adapters which will work in those areas.