This is a pretty nice piece of equipment, that will be effective for most people.
The only possible problem is that the 11b finger pull will likely not be enough if you are considering using these for genuinely serious use (weight-training, power-lifting, climbing etc.), which is what these are supposedly aimed at.
So unless they make a significantly harder set you'll probably only really use them to warm up before moving onto stronger grippers or other grip building exercises.
Which is a shame as they do a very good job of exercising your whole grip (including pinky), and so there must be a market for say 15lb and 20lb versions of these.