What do you  load your StrongerGrip equipment with?  BB's, lead shot, steel shot, sand.  What you choose depends on how heavy you will be able to get them.  Lead will be the choice to get them as heavy as possible.  A good place to find lead shot is at rotometals.com.  They have reclaimed shot at a real nice price.  Another alternative is sandblasting media.  You can get this in several grits and also in beads(balls).  I'm going to carry the steel grit media.  It's steel sand basically.  Nice and dense, and when it's dropped it lands in a pile instead of a thousand tiny balls going everywhere!  That's experience talking.   So if you do not have access to a sandblasting supply store or just don't want to hassle with trying to find one, we've got some for you.