The white, rectangular power adapters included with recent Apple laptops are 110-240V models, which means they work around the world; you just need the right plug. Apple offers a useful World Travel Adapter Kit ($39) that includes six plugs for electrical outlets around the world; you just slide out the stock plug on the power adapter and replace it with the appropriate plug for the country in which you’re traveling. (This adapter kit also works with Apple’s USB and FireWire iPod power adapters.)
But one complaint some users have had about Apple’s adapter set is that, because the plugs connect directly to the adapter, it can be difficult to plug in the adapter in tight quarters; in fact, if a wall outlet doesn’t have much clearance, you may not be able to plug in the adapter at all. (Apple’s six-foot power cable works only in the country of purchase.)
One solution to this problem is to instead buy a standard international plug adapter (such as this Belkin model) and then use your U.S. cable. Another solution is Incipio’s Continental Companion Cables ($35), a.k.a., the Companion World Travel Cables. This set of cables gives you functionality similar to that of Apple’s collection of plugs, but in cable form. Specifically, you get four foot-long cables, each with a connector for Apple’s AC adapters on one end and one of four international outlet plugs on the other. The result is compatibility with most non-U.S. outlets as well as a foot of flexible cable. Incipio includes a mesh travel bag for carrying the cables and your AC adapter.
Of course, the set of cables is heavier and bulkier than Apple’s plug set—the cables weigh approximately 10 ounces together. But few people need all the cables/plugs at once—most of us know which countries we’re visiting before we leave, so we can bring only those cable/plugs we need. In that respect, the difference in size and weight isn’t an unreasonable tradeoff for the advantage of having a bit of cable slack.
On the other hand, Incipio’s cables are missing one feature of Apple’s plugs. Apple’s AC adapters all have a protruding metal disk next to the plug connector; the plugs themselves each have a groove into which this disk slides to “anchor” the plug firmly in place. Incipio’s cable connectors are missing this groove, so when you connect the cable to the adapter, it’s held in place by only the connection between the plug and the adapter’s electrical contacts. In my testing using the U.S. cable, I didn’t find this to be an issue, but I don’t know if this connector design will result in more wear-and-tear on the adapter’s electrical contacts over the long run.
(As an aside, although the Companion Cables set is intended for international use, I got quite a bit of utility out of the U.S. cable. It was handy for those times when my AC adapter wouldn’t quite fit in a wall outlet by itself, but I didn’t want to dig (or bring along) out my six-foot Apple cable. It was also great in places—cafes, airports, etc.—where outlets were cramped and everyone was trying to plug in bulky AC adapters.)
Oddly, Apple’s adapter kit includes six plugs and lists compatibility with eight areas of the world (North America, Japan, China, United Kingdom, Continental Europe, Korea, Australia, and Hong Kong), while Incipio’s cable set includes only four plugs but lists compatibility with many more areas (including South America, New Zealand, the Caribbean, the Middle East, and Africa). With respect to compatibility, Incipio's representative told me that the company is simply more specific about stating where their product works. This comment implies that Apple’s adapter set will work in the same locations but that Apple, for whatever reason, doesn’t list them all. I don’t know enough about the standard electrical outlets in places such as Africa, the Middle East, and South America to know if Apple’s adapter kit will indeed work in these locations.
As for how Incipio is able to offer similar compatibility with two fewer plugs, the representative told me that one of the Apple kit’s additional plugs is essentially an extra U.S. plug and the other is a plug specifically for Korea—one of the locations Incipio’s kit doesn’t support.