It doesn't measure up to the ambitious prostheses pursued by DARPA or DEKA Labs; it doesn't plug into the nervous system or recreate the missing five-fingered hand synthetically. But it's not trying to. What it does, at least in concept, is offer a feasible, immediate solution to problems faced by those missing a partial limb. And it does so without great complexity or expense. You won't praise for virtues like simplicity and affordability often from PopSci (no one wants to take teleportation holidays to robot-populated moon cities as much as we do), but when something works, it works.