From Ubuntu11.04's help, it says: What is the meta key? The the meta key is key between the Ctrl and Alt keys on your keyboard. It may sometimes be called the windows key, logo key, system key, or even the Ubuntu key. If you have an Apple keyboard, there will not be a meta key on your keyboard. The Command (Cmd) key can be used instead. The meta key serves a special function in Unity. If you press the meta key, the Dash is displayed.
The main issue with the hoverboard is the battery. According to CNET, most hoverboards use lithium ion batteries, the kind often used in laptops and cell phones. But the liquid inside these batteries is flammable, and hoverboards (which have been produced and marketed out of thousands of essentially nameless factories in China) haven't adhered to a singular set of safety standards, and could very well be dangerous.
VRLA cells may be made of flat plates similar to a conventional flooded leadâacid battery, or may be made in a spiral roll form to make cylindrical cells. VRLA batteries have a pressure relief valve which will activate when the battery starts building pressure of hydrogen gas, generally a result of being recharged.