It's impossible to convey in a photo how light Lenovo's new ultraportable, the LaVie HZ550, is. So instead I'll say this: When I first picked it up, I was sure I was handling a prototype; some sort of dummy unit without any actual components inside. In fact, though, the HZ550 is very real, and at 1.72 pounds, it's stupidly, record-breakingly compact; in fact, Lenovo claims this is the world's lightest 13-inch laptop. What's more, the company just announced what it says is the lightest 13-inch convertible notebook: a machine called the HZ750, which has a 360-degree hinge that allows it to fold back into tablet mode. At 2.04 pounds, it's lighter than any laptop with a touchscreen and rotating hinge has the right to be. Either way, even in a field of increasingly skinny notebooks, both of these stand out.