This kind of device used to come with iMacs as standard and was white and plastic. This version is essentially the same, but - in keeping with Apple's mission to manufacture everything in a basic uniform design - it now comes in anodised aluminium. The change is a step up. It's longer and narrower than its white predecessor, and feels about 200% sturdier and easier to hold. In fact, it's more than just easy to hold, it's great. The convex, seamless aluminium just seems to invite being touched; the only thing that's (strangely) missing is an engraved Apple logo.
The remote uses infrared technology. The title says it's for iPhone or iPod, but it'll only work with those devices via an attached dock or infrared receiver. It's more readily used with iMac, MacBook, Mac mini or Apple TV, all of which come with infrared receivers built-in. Some people prefer to use Apple's free Remote app on an iPhone or iPod touch, to navigate an Apple TV for example, but I find the app to be unwieldy and unduly draining on the device's battery. This remote uses a single CR 2032, which is good for months and months of use.
If you use an old plastic Apple remote a lot, it's worth upgrading to this one for the great feeling of the exterior and its improved durability. Until Apple comes up a dedicated, more complex remote (with a screen), this little device is the best Apple remote going, and the low price makes it well worth it.