This product is based upon the same concept as our solid cast iron adjustable and functions just as well. You use your own 10# weights used in your dumbells (with 1 inch hole). A youtube videos of this product can be found at: http://www.youtube.com/watch?v=8q57tro2K_Y or http://www.youtube.com/watch?v=MLMw6oqIhoo or http://www.youtube.com/watch?v=BgG_zEU0YGg.