Chippy is checking out Ultrabooks at IDF this week and he had a chance to get his hands on the NEC Lavie Z Ultrabook. What makes this unit stand out is its incredible weight. This is a 13.3″ screen; at just 876 grams, the Lavie Z is the world’s lightest Ultrabook in it’s class, even lighter than many of the Ultrabooks in the size class below it. For example. the Asus UX21A with an 11.6″ screen is about 1100 grams.