KettleBells are cast iron weights, which resemble a cannonball with a handle. A legendary Russian exercise device, the kettlebell has long been a favorite for those seeking a special edge in strength and endurance. KettleBell training develops strength, power, endurance and balance. KettleBell workouts have long been a favorite of throwers, jumpers, sprinters and hurdlers. You can perform squats, pulls, overhead throws and rotational training plus much more.