The Thames & Kosmos Mega Cyborg Hand STEM experiment kit requires no batteries or cords. How does it work? It gets its power from air pressure, water, and your hand. Slip your hand into this huge hydraulic glove, and then you can move your fingers to move the mechanical fingers. Feel like a true cyborg with this hand, which is made up of a whopping 203 plastic pieces! Then, fill the piston tubes in this STEM experiment kit with water. They are what allow the fingers to close, open, and grip objects with force. Adjust it to fit your hands and configure it in any of three ways: left-handed, right-handed, and claw-like with a center thumb. In fact, every finger joint adjusts to offer precise movements, so you can grab larger items like bottles and smaller items like pencils.