Definitely works! We've used it for everything from soda bottles to large peanut butter jars. I have bad arthritis in both hands and another member of the household only has the use of one hand. We either had to get very creative or do without if there was not someone else at home. Even when we aren't alone, it's nice to be able to be more independent.
This makes opening jars as easy as claimed. Now that I have it I wouldn't do without it.
I purchased this because I broke my right wrist several months ago, and I have no strength in that hand now. Someone recommended this to me and it works beautifully. So simple! I am even able to open prescription bottles with my left hand by simply pushing up as I turn the bottle.
This opens them nicely and was very easy to install. I wasn't sure if I wanted the hand-held tool or an automatic jar opener, but when I saw this product and the longevity of the company, I went with this and very happy I did. I have a smaller kitchen and not a ton of storage space, so it made sense for that reason as well.