This is a more advanced version of the pistol squat and make sure you have mastered the pistol squat with your body weight only before you give this a try.
Pick up a kettle bell and hold it by the sides of the handle; hold the kettlebell in front of your chest. Pick one leg up off the floor and then you are ready to begin. Start the movement by pushing your hips back and sitting back into the squat. Bend through your knee and squat all the way down until your thigh is parallel to the floor. Hold the kettlebell still throughout the entire movement. Hold the bottom position of the squat and then push through your heel and return to the starting position. Repeat this movement until you have completed your set and then repeat with your opposite leg.
Make sure to keep your head up and chest out during this movement. Look straight ahead, this will help your balance which is very important for this movement. Also, hold your core very tight during this exercise.