These weights are well made and obviously easy to use. I actually got two sets of two and use simultaneously on ankles and wrists. The weight isn't much if you're looking for a heavy and focused workout, but if you wear them while doing other exercises they can considerably add to the level of difficulty and contribute to the result.
These are ideal for more 'casual' users who are not so gym-minded (we're still the majority, I suspect). I wear the weights around the house, partly while doing some light exercise like stretches or running on the spot, but I also leave them on while doing anything, from housework to reading. The result is amazing: you get used to them in a few seconds and go about your business normally, but the extra kg on each arm and leg makes you exercise without thinking about it. Obviously you can wear them outside the house around the ankles (they're discreet) and intensify your walking even in short distances. I've been using them casually for about a month now and I already have visible results (i.e. more toned shoulders, biceps etc.). Even if you're not aiming for specific results, they're a nice way to burn more calories without actually working out.
I guess the above would apply to any similar product, but from what I've seen so far, the specific product is well made and durable, and I'd recommend it highly.