The one end has your standard USB end that would connect to your computer or a wall adapter. Then you got the 3 cords running from that. The first is your regular micro USB. This USB will fit most smartphones and MP3 players today.
The next is Apple's new lightning charger for the iPhone 5 and I assume the iPod Touch 5th Gen. I actually finally got an iPhone 5 on Monday so I've been able to test it out and it works quite well. I've read some 3rd party lightning cords won't fit when you have a case on the phone. The one on this cord is slightly bigger that the one that came with the phone but it fits just fine with my case.
The last cord is Apple's old 30 pin connector. Useable on iPhone 4S and before. As well is iPad and iPods. I didn't get a chance to use that cord since I only have the iPhone 5.
But wait! I know what you're thinking. "How is it 4 in 1 when there is only 3 cords?" Well if you take that last cord. The Apple 30 pin connector and flip it over you'll see that is says SAM on it. With the cord this side up it will fit into and work very well with Samsung devices that us their proprietary connector. Now I was able to use this cord since I do have a Galaxy Note 10.1 tablet. And like the rest of the cords it works well.
This cord is quite handy in a pinch and is very nice to have an extra cord lying around. Especially one that can work with so many devices! I love it and recommend it to anyone who has a multitude of devices across the vast range of connectors!