The TK1650 is a kit consisting of a PB1650 voltage converter, 5 additional adapters for plugging the voltage converter into other types of outlets, and a convenient carrying case for everything. By attaching the appropriate adapter to the PB1650's built-in plug (whichever adapter matches the outlet present) it can be used in over 150 countries.
If you need to operate a North American 110-120 volt hair dryer, curling iron, heating pad, lamp/light, or other non-electronic appliance in a country where the voltage supplied by the electrical outlets is 220-240 volts, the TK1650 voltage converter is probably a better solution than a step down transformer. Voltage converters do the same thing transformers do. Namely, they take the 220-240 volt electricity supplied in most countries, and convert the voltage down to 110-120 volts for use by the appliance. While voltage converters and transformers do the same thing, they do it in different ways, and the difference is very important.
The advantage of a voltage converter is that for high-wattage appliances like hair dryers (which are often 1200-1500 watts) and other simple heating appliances, a voltage converter is a lot smaller, lighter, less expensive and more convenient than a transformer with a similar wattage capacity. A 1500 watt transformer could weigh close to 30 pounds! The TK1650 weighs about 2 pounds.
The downside is that while a voltage converter works fine for a simple non-electronic appliance like a hair dryer, voltage converters should not be used with electronics like laptops, televisions, stereos, etc. Never plug a laptop into a voltage converter.
But if you need to plug in a beverage heater, clothes steamer, coffee maker, electric blanket, food/bottle warmer, hair dryer, hair roller set, heating pad, hot plate, incandescent lamp, iron or something like that, a voltage converter should do the job. As long as the appliance doesn't contain any electronics like a clock or timer, a digital temperature control, an auto-off feature or anything like that.
Be sure that your appliance's plug only has the two vertical blades, and does not have the third, round grounding pin. The socket on the TK1650 voltage converter does not accept a 3-pin grounded plug.
The TK1650 is a "combo unit" in that it has two modes. In "low power mode" it functions as a voltage transformer, and is safe for use with electronics. But in low power mode, the TK1650 can only handle electronics up to 50 watts. So anything electronic would have to be very low power. Battery chargers and electric shavers are often below 50 watts, and therefore can usually be safely used with the TK1650. But you have to be absolutely, positively sure that it's less than 50 watts. Otherwise, the TK1650 will switch over to "high power mode" where it can handle up to 1600 watts, but only for non-electronic heating appliances.
The TK1650 voltage converter is built with a CEE 7/16 "Europlug" type of plug, and ships with five adapters to connect to its built-in plug so that it can plug into other types of outlets. By attaching the appropriate adapter matching the type of outlet present, the TK1650 can be used in over 150 countries!
But do I need a voltage converter? Or would a plug adapter be enough?
Well, that depends on whether or not your hair dryer, curling iron or other heating appliance is compatible with 220-240 volt electricity. Most appliances of that nature are not, but a growing number of hair care appliances are being manufactured to be switchable between 110-120 volts and 220-240 volts. Your particular model may or may not be.
Electrical sockets in most parts of the world outside of North America generally supply electricity at between 220 and 240 volts AC. If you're plugging in an appliance that was built for 220-240 volt electrical input, or an appliance that is compatible with multiple voltages, then an adapter is all you need.
But plug adapters do not change voltage, so the electricity coming through the adapter will still be the same 220-240 volts the socket is supplying. North American sockets supply electricity at between 110 and 120 volts, far lower than in most of the rest of the world. Consequently, North American appliances are generally built for 110-120 volts. But that doesn't mean that your specific appliance isn't already compatible with the higher voltage -- it may very well be.
So how do I know whether or not my appliance is compatible with the local voltage at my destination?
Short answer: The only way to know is to check, and there's absolutely no getting around that crucial step. Electricity is nothing to mess around with, and assuming can be bad news. If you're wrong, you could "fry" your appliance, or worse yet, start a fire.
That being said, generally speaking, most modern "digital-age" appliances (especially ones that run on batteries) are being built to be compatible with all worldwide voltages, from 100 volts in Japan to 240 volts in the United Kingdom. This usually includes things like laptops, PDAs, cell phones, digital cameras, digital camcorders, many portable video game devices, digital music players, etc. More and more personal grooming items like hair dryers curling irons, shavers (especially cordless ones) and such are being built to be compatible with multiple voltages as well, but most of them aren't.
"Conventional appliances" like kitchen items, audio/video equipment, vacuum cleaners, lamps and lights, and most bath appliances are not compatible with multiple voltages. Again, the only way to know is to check. A common misconception is that there's any such thing as a "standard" electrical input for appliances. There's not. They're all different.
Okay, so how do I find this info for my specific appliance?
The electrical input specifications will appear on a label on the appliance itself, or on its charger or AC adapter if it uses one, near where the brand name and model number appear. Look for the word "input." As a last resort, you could check the back of the manual, but 99 times out of 100, it will be on the appliance's or charger's label. The input voltage is usually abbreviated to "V" and it should look something like this:
Input: ~100-240V 50/60Hz 65W -- This means the appliance is compatible with multiple voltages. This item can be brought just about anywhere in the world, and any difference in voltage is basically irrelevant. The appliance (or charger) adjusts itself to whatever voltage it receives. The only issue is whether or not the plug can physically interface with the socket. The appropriate travel plug adapter is all that's needed.
---or--- Input: 115/230V 50/60Hz 200W -- This means that the appliance can be switched between 110-120 volts in North America, and 220-240 volts in other parts of the world. This is common of desktop computers and some hair dryers/curling irons/etc. You probably have to physically flip a switch somewhere, but as long as that switch is in the proper position and you have the appropriate plug adapter, you're fine.
---or--- Input: 120V 60Hz 2.8A -- This means that the appliance is only compatible with a single voltage, in this case, 120 volts. If the socket is 220-240V, then an adapter by itself isn't enough, because travel plug adapters do not change the voltage supplied by the socket. Plugging it in with just an adapter can "fry" it (if you're lucky, that's all that will happen) because the voltage is too high for the appliance to handle. To use this appliance safely, the voltage needs to be changed from 220-240 volts to 110-120 volts by way of a voltage converter or transformer.