Kettlebells are weights that can be lifted like ordinary dumbells, but can also be swung about for an intense cardio workout. With kettlebells you can have a workout in very little space that will get your heart pumping and exercise your whole body. With a pair of these you can burn up just as many calories, as going for a run, all you need is the room to swing your arms. There are hundreds of exercises you can do with a KB, exercising your whole body, in little space.