WattOS is a lightweight, rock solid, generic distribution, that is, you can use it for anything, without focusing on a certain niche like some other Linux distributions that we have analyzed on our website. Therefore, the philosophy with which this operating system has been created is to provide a lightweight distribution without having to give up certain things.
WattOS allows good energy savings, and can be installed on old hardware due to its lightness (it does not consume too many resources). All thanks to the work that the developers have done regarding the base, which in this case is Ubuntu. You already know that with WattOS 8 they decided to leave the Canonical distro to become based on Debian, but now they returned with version 9 to use the Ubuntu distribution as a reference.
If for some reason it does not seem light enough, there is an even smaller version called Microwatt, which also had changes going from PekWM or openbox to i3 window manager. You already know that i3 is one of the lightweight window managers based on the tiling philosophy (it organizes the windows in tiles and does not overlap them, to occupy all the space on the desktop), something that for some is not at all comfortable and for other users it is the most practical ... a matter of taste.
Returning to WattOS, now in its new version 10 we can find an environment of LXDE desk, more popular and complex than i3. In addition, the Linux kernel has been updated to a more modern version, without forgetting the packages that are included by default and pre-installed on this system, which have also been updated. Among the repertoire of packages there are packages to cover almost all needs, as well as specific software to improve power management in laptops.