If he tenses his bicep the hand closes, if he tenses his tricep the hand opens. It's got multiple different shapes it can form, and the level of control is good enough for him to pick up eggs!
The question now is - how long until the technology is better than biology?
(The big missing thing, obviously, is feedback. That's not going to be an easy one to solve.)
More info here.
Original post on Dreamwidth - there are comments there.