This movement is not just for biceps. This is going to hammer your grip, work the upper back and shoulders and some legs and abs even.
The sandbag used is called a "Sea Bag" and can be found at army navy stores or possibly in Ferruggia's closet for some odd reason.
Definitely put some body into these on the way up, on the way down you should be lowering with good posture though.
Please don't bring this stuff to your local Bally's and blame us for your insanity. We're only here to help 🙂