these O-rings work and do save your baits but a cheaper thing that I found out is to buy some small black tie-wraps and use those, they work better and are a lot cheaper.
Really struggled with these, had a tough time hooking smaller bass pound to pound anahalf fish. Larger and more aggressive fish were fine. But the soft bite on smaller fish I was lucky to hook 25%.
The wacky tool and "O" rings make a Senko last about 10 times longer and it doesn't affect the effectiveness of the Senko. I've never found a better lure and now it is even more cost effective! Last summer I caught and released over 1,000 bass using this combination so I know it works!