BTI Replacement Battery for Lenovo ThinkPad X240, X250, X260, (0C52861-BTI)
Hands on with the ThinkPad X240: Two batteries are better than one | ZDNet
The ThinkPad Power Bridge is dead (and why that's a good thing) — Part 1 | by George Kushnir (https://n4ru.it) | Medium
Lenovo ThinkPad X240 Review: Lenovo's ThinkPad X240 is a very different beast compared to the X230, but still one of the best small laptops on the market - Notebooks - Ultraportable -