The X Series is the main high-end ultraportable ThinkPad line, offering a lightweight, highly portable laptop with moderate performance. The current sub-lines for the X series includes:
The daughter line includes the X1 Tablet (not to be confused with the 2005-2013 X Series tablets).
The mainstream current "workhorse" models is a X13 and X13 Yoga, the 13" successors of the classic discontinued 12" line of Lenovo X Series ThinkPads.
The premium 14"/15" thin-and-light line were the 13.3" ThinkPad models (the X300/X301) with ultrabay CD-ROM and removable battery, but are now replaced by the modern premium X1-series ultrabook line, such as the X1 Carbon, X1 Yoga, and X1 Extreme sub-series.
Discontinued mainstream lines such as the 12" X200(s), X201(s), and X220 models could be ordered with all of the high-end ThinkPad features (like Trackpoint, ThinkLight, a 7-row keyboard, a docking port, hot-swappable HDD, solid magnesium case and optional slice battery). The discontinued 12.5" X220 and X230 still featured a roll cage, a ThinkLight, and an optional premium IPS display (the first IPS display on a non-tablet ThinkPad since the T60p), but the 7-row keyboard was offered only with the X220. However, it lacked the lid latch mechanism which was present on the previous X200 and X201 versions. The discontinued slim 12" line contained only X200s and X201s with low power CPUs and high resolution displays, and X230s with low power CPUs. The 12.5" X series ThinkPads (such as X240 and later) had a more simplified design, and last 12" X280 model had only the Trackpoint feature, partially magnesium case and simplified docking port.
The obsolete low-cost 11.6" (netbook line) X100e and X120e were are all plastic, lacking both the latch and the ThinkLight, and using a variant of the island keyboard (known as chiclet keyboard) found on the Edge series. The X100e was also offered in red in addition to blue, and white in some countries. Those were more like high-end netbooks, whereas the X200 series were more like full ultraportables, featuring Intel Core (previously Core 2 and Celeron) series CPUs rather than AMD netbook CPUs.
The X Series with "tablet" suffixes is an outdated variant of the 12" X Series models, with low voltage CPUs and a flip-screen tablet resistive touchscreen. These include the traditional ThinkPad features, and have been noted for using a higher quality AFFS-type screen with better viewing angles compared to the screens used on other ThinkPads.
Current docking stations (or docks) add much of the functional abilities of a desktop computer, including multiple display outputs, additional USB ports, and occasionally other features. This allows the ThinkPads to be connected and disconnected from various peripherals quickly and easily.
Recent docks connect via a proprietary connector located on the underside of the laptops; or via USB C.