The hand is rigged and you have the control of every joint of the fingers and wrist, some parts are locked in some directions to prevent unacceptable moves, but its easy to unlocked them in settings.
The rig permits also to control every single flip of the fingers, front and back, so you can open completely the hand and show the inside.
In the wrist control there are fist and spread controls, and the master control of the arm can be parented to a potential forearm.
You can buy the low poly Robot Hand on 
Number of joints: 54
Poligons: 5,689
Vertices: 6,582
samuel 23 May 2015
need (2) DIY 3d robotic arm, will use it with servo motor and arduino
tribio 23 May 2015 — Post Author
You can buy it on turbosquid, but be carefull it’s just a 3d sowtware model, it’s NOT a real one!
And it’s not ready to be printed!