I did not think it was possible, but Lenovo has somehow managed to shed more weight from its premium ThinkPad X1 Carbon ultrabook.

Last year's model was svelte for a 14-inch laptop at 1.3kg. But the latest X1 Carbon weighs just 1.18kg, less than the 13-inch Apple MacBook Air.

Lenovo says it uses satellite- grade carbon fibre, making the X1 Carbon the toughest ThinkPad ever made. It has backed its claim by having the ultrabook pass numerous military-grade endurance tests conducted in extreme conditions.

In my own less-than-scientific testing, in which I attempted to bend the laptop with all my strength, the X1 Carbon is surprisingly rigid, given that it is thinner than the MacBook Air.

The keyboard is spill-resistant. Perhaps wary of offending its more fanatical users after receiving flak for tweaking the 2014 model, Lenovo has resisted the urge to tinker with the keyboard on the new X1 Carbon. It is practically identical to last year's version and has excellent key travel.

However, I am still not used to having the Fn key on the outside left corner. On most keyboards, this spot is taken by the Ctrl key.

But ThinkPads have been using this layout for years. The official reason: It is easy for users to aim for the corner, without looking, for certain keystroke combinations.

For instance, you will not have to fumble when turning on the backlight in the dark, as it is easily activated by pressing the Fn key and the Space bar.

Non-ThinkPad users will likely take a while to adjust. To be fair, Lenovo lets users swop the Fn and Ctrl keys in the BIOS settings to the standard keyboard layout.

Compared with the previous model, the 14-inch screen seems brighter. Viewing angles are very wide and the matt finish reduces reflection. However, the icons and text are small - albeit sharp - because of the high screen resolution (2,560 x 1,440 pixels). You probably have to enlarge the size of the text and icons via the settings.

There is no longer a touchscreen version of the X1 Carbon, as Lenovo has spun off the touchscreen variant of the X1 Carbon to its own distinct line, called the X1 Yoga.

But this makes it simple for consumers - the X1 Carbon for those who prefer a traditional clamshell laptop, and the X1 Yoga for those who want a convertible with a touch display and the ability to switch between four usage modes.

Besides upgrading the processor to the latest Intel Skylake variants, Lenovo has also changed the X1 Carbon's fingerprint sensor from a swipe-based type to the touch- based version found on the latest smartphones. In my testing, the new fingerprint sensor feels more accurate. It was quick and flawless.

But I was a bit disappointed that Lenovo has not embraced the new USB Type-C interface, choosing instead to equip the X1 Carbon with three USB 3.0 ports. The laptop lacks a Thunderbolt port, with Lenovo sticking to its proprietary OneLink+ port, which can be used for connecting an optional dock or cable for Ethernet and display outputs.

Those who prefer a cable-free work area can consider the optional WiGig docking station, which connects to the X1 Carbon wirelessly to transmit video, audio and Ethernet signals.

My review set also comes with a 4G LTE module that lets the laptop access the Internet with a data plan.

The new X1 Carbon is slightly faster than last year's model in PCMark 8. Battery life, too, has improved from 6.5 hours to seven hours.

•A top ultrabook that is worth its premium price tag.