Ok these are by far the best kegal exerciser/ben wa balls around! First off they are just the right size and can work their way up in size/weight. With the harness and removable balls you can just do one ball or put two in the harness. So nice is the pull string if only one ball is used for easier retrieval. Two different weights for when you get more experienced! While pricey - These are well worth the money, as there is nothing like them as the inner ball vibrates while in the body stimulating your muscles to contract and almost putting me into an orgasm multiple times! Great Buy!