Travel power can be confusing, and getting it wrong can potentially be dangerous, even if just to your devices. (Note: if you don't know the difference between "input voltage" and "plug type", please read the Travel Power info at the bottom. It is very important.)

With regard to these specific adapters, I was recently in Italy for 30 days, stayed in 5 different hotels and 5 different homes - some old and some new. These adapters worked everywhere I tried them. (EDIT 2014: I later bought the Australia/China Type I and used them in New Zealand - same positive experience, but mainly used in an RV/Campervan).

The receptacles (USA, anyway) are tight enough so plugs do not fall out of them, but not overly so (so you can still pull your plugs out!).

The added benefit that I didn't read (realize?) until I received them was that you can actually plug two devices in at one time (but only one 3-prong at a time & as a safety precaution, don't daisy-chain them). The 3-prong goes into the "holed" side you can see in the photo, and the two prong would go into the side you cannot see (also has holes) - so, if there's just one outlet at the bedside, you can charge your phone/tablet while also leaving the lamp plugged in (just remember to take it with you when you leave - the adapter, not the lamp). {EDIT 2016: commenter Jay reported his were only able to accomodate one plugged-in item.}

If you think you will only need one, then bring two. That way you will have a back-up in case you lose one/break one/lend one out. I figured two would be good, so I brought three. It worked out, as I did lend one out and I was able to keep one in my purse and one in my suitcase - for easy access.

I used these with polarized, non-polarized, & 3-prong USA plugs (camera battery, phone, ipod, laptop, usb-block, various lamps), plugged into various 3-prong italian outlets.

It was nice to have the added benefit of the second-device feature, but I would have also preferred these plugs be white, as they would be easier to find in my bag (and blend into the walls better - most were white). {The product photo is currently showing a white plug, which is the color I expected to receive}. (EDIT, 2014: mine came black)

EDIT 2015, with TIPS on Travel Power:

Many people I talk to about this subject don't know what to look for and often, they end up spending more than they really need to. So, I'm augmenting my review with a basic overview of what's needed for travel power purposes. If you don't already know the difference between plug and voltage converters, check out the info below. This is what I tell my peeps when they travel.

You'll need to consider two things when it comes to travel power: 1. Shape and 2. Voltage

1. Shape
If your home-country-shaped plugs are different than your destination-country-shaped plugs, you'll have to buy the plug adapters that convert them. They are usually a "Type", like these Italian Type-L plugs. (you can find the specifics of your countries with a google search). Many countries share a type, so if you are traveling to more than one country, you might get lucky with one type (or have a type already from another trip that works for a different trip). Be sure to buy an adapter that has the "male" type/shape of your destination, and the "female" of your home country (if you don't know what that means, just liken them to basic 'human genital anatomy'). Some, like these, have multiple "female" type options. And, others have multiple "male" type options, using a variety of sliders. The simplest version of these plugs (one type to one other type) are usually pretty inexpensive (US $2-20), depending on the Type and the supplier. The grounded and also the multi-type versions are usually on the mid-to-higher end of that cost spectrum. Even more expensive, are some that have the added benefit of also claiming to have surge protection. I bought one of these for India, due to their high incidence of power issues.

2. Voltage
You'll have to check the typical outlet voltage for the country(-ies) you're visiting and compare that to your home country to know if you'll need to consider voltage conversion while you're on your trip. Again, a simple google search (or peek at the respective travel books) will give you this info. You're generally looking for numbers like 100V, 110V, 220V, 240V, etc.

If they differ, you usually have two options:

A. Buy a converter.
I've never bought one, but I've seen them in the usual places, including here on Amazon, as well as the "Travel" aisles in Target, Walmart, etc. Airports and travel stores also usually have them.

B. Use / Buy "switching" or universal adapters for your electronics.
Most actually already come with them, especially many phones, laptops, and mobile devices. In addition, USB-powered chargers are usually (if not always) universal. This is based on my experience, I am not an expert. So, before you spend money on a converter (that will take up precious space and weight in your luggage), check the very, very, very fine print on the wall plugs/brick adapters of your devices for writing that says something like "Input: 100-240V". See photos for what to look for. If the country(-ies) you are visiting are within that range (which you'll know from that google search), then you don't need a voltage adapter, just a "shape / outlet" adapter. Yay for $avings!

Most of the stories I've heard about travelers blowing outlets and whatnot involve heating devices such as curling irons or hair dryers. I don't travel with those, but I do know that they make "travel" ones that, in addition to folding or being smaller, also usually have a "voltage switching" option. With mobile phones and the smaller devices, this switching is usually done automatically. With these heating devices, the switching may need to be done manually, so be SURE to double-check that for yourself or others in your party, in order to prevent a dangerous or at least embarrassing situation.

Of course, your third option would be to "unplug" completely and travel like it's 1985. Radical!

I rely on reviews to help me make informed buying decisions. I hope this review helped you!

I picked these up for a filter I purchased for my turtle's tank; turned out the filter, which is hard to find to begin with, had a UK cord. I picked these up (they're an absolute steal) and used one to convert the filter to something I could use. That said, the filter still isn't working completely. I don't know if this is a problem with the filter itself, or with the outlet travel plug adapter; when I tried the adaptor with another UK-cord item we have in our house, it worked generally well but the power seemed to be a little off, as though these was a loss of power between the adapter and the item. It seemed to work fine (minus the power loss) but I am not sure if I would pick these up again. 4 stars for being a good price and for generally working.

These plug adapters are simple and solid. When you open the package you know that they are well built. We bought the C, L and I types for our recent trip to Chile and Argentina. They fit snugly into the 220 wall outlet and our 110 volt plugs fit snugly into these adapters. Adapters don't really have to function, they merely allow you to use a 110 volt US blade into a different type of wall outlet. They DO NOT convert the current from 220 to 110. But we needed the ability to plug our myriad of chargers (iPad, phone, camera, etc) into the wall to recharge our devices. Most (probably all) chargers work with 220 volt as well as 110, IF you can plug them in. These adapters allowed us to do just that.

We used this plug adapter in Switzerland recently and it worked perfectly. There was one situation where the outlet was a wall switch & outlet combination and the fit was about 1/16" to tight....but it worked. Should have taken a picture. I'll use this adapter again on my next visit. Please understand this is a "PLUG" adapter as stated by the seller and not a "Voltage Converter". The voltage is still 220v which is fine for my use as I used the adapter so I could charge my iphone. In a very small font on the plug side of the Apple Charger it say it uses both 220v and 110v. .

While they can work, they are loose so for example my hair straightener would keep getting unplugged; plus they stick out so you can only use one plug at the time.
I would recommend going with OREI Grounded Universal 2 in 1 instead - I had purchased both for my recent trip to Europe and ended up only using the OREI since these guys were such a pain. These are the cheaper version and they will work; I just prefer the other option.

I purchased this package of three for myself, my husband, and my son for our trip to Ireland. The adapters worked perfectly, were simple and small, and even worked with the miniature power strips we brought.

Worked great in both Paris and Rome. No issues. Great price and held up wonderfully the whole trip! Was grateful, as I heard of many others who have had poor experiences buying other brands from different buyers. Would definitely buy again!

Was able to use these on the trip to Italy however not all places supported the three prongs. More than half only supported two prongs so you should have one of each. Luckily we had both so we were always wired. It is also somewhat bulky but may be this contributes to it being rugged. After plugging the American cord into the adapter, you notice how far everything protrudes into the space. For example on Lufthansa I was constantly hitting the arrangement with my leg and it would be knocked off. Overall it worked as expected.