This exercise is very challenging on your grip and hands.
You'll need a safety squat bar. Grab the fat, padded part of the bar. Keep the bar in front of your face. Press the bar overhead. Be sure to squeeze the bar tightly because it will want to wobble back and forth. Slowly lower the bar back down to your chest and repeat for desired number of reps.

I really like this exercise and I caution using alot of weight at first.