These neat little LCD panels, in two sizes, go black when a current is passed through them. Perfect for creating your own pair of "deal with it" sunglasses!
Essentially single pixel LCD displays, these panels polarise and go black (completely opaque) when you pass 3V through them, and then de-polarise (become transparent) when pulled low or shorted. Easy!
You can treat the LCD shutter like a low value capacitor. Once energised, they will hold their polarised/opaque state, but slowly leak charge over time and become de-polarised/transparent again. The amount of current required to charge the LCD shutter is extremely low, as with most LCDs.
They are best viewed from directly in front, as other viewing angles may lower the opacity slightly. The displays are made of glass and have sharp corners, so take care when handling them.