LAS VEGAS -- Laptops and hybrids with 13-inch screens are already very thin and light, with the popular MacBook Air hitting 2.96 pounds (1.3kg) and the Yoga 3 Pro at 2.6 pounds (1.2kg). Lenovo is making a big push towards even lighter systems with the new LaVie Z series, which promises a 13-inch clamshell laptop at 1.72 pounds (0.7kg) and a Yoga-style 13-inch hybrid at 2.04 pounds (0.9kg).

The company claims that would be the lightest available model in both 13-inch laptops and hybrids, and considering how light something like the Yoga 3 Pro already feels, it could be a major shift in what we expect from portable PC design.

The LaVie Z is actually the product of a partnership Lenovo has had with NEC since 2011, where the two companies would design and sell NEC-branded PCs intended only for the Japanese market. These two systems are the first from this partnership that will be sold outside of Japan.

The laptop version, the LaVie Z HZ550, and the hybrid version, called the HZ750, bring the weight down thanks to a magnesium-lithium chassis, which Lenovo says is 50 percent lighter than aluminum and just as strong other magnesium alloy materials.

Both have screens that go up to 2,560x1,440 resolution, and will use CPUs from Intel's new fifth-generation Core i series, also known as "Broadwell." The laptop version gets a Core i5, while the hybrid can go up to a Core i7. 128GB of SSD storage is standard in both versions.

While only the HZ750 folds back into a tablet shape, just like Lenovo's Yoga products, the clamshell HZ550 version still opens a full 180 degrees. According to Lenovo's specs, the hybrid has a standard 44Whr battery, while the laptop has a lower-capacity 29.6Whr battery. That may lead to shorter run times, but getting a 13-inch laptop down to about 1.7 pounds is hard to do without making some adjustments, and the lighter carry weight may be worth the tradeoff.