Openbox is a great window manager, but it lack it's dedicated system monitoring tools. Often they must be installed from oher desktop environments, along with a lot of useless dependancies.
ObSuite is a light and modulable alternative to those packages. It include five basic tools which make it easy to manage or monitor volume, network, bluetooth, battery and backlight. It is mostly meant for laptops, yet also interesting for desktop computers as the unused modules are easily disabled. In both case, bluetooth is great for a quick access to connect/disconnect methods for selected devices, and the network module allow some feedback when using wpa_supplicant alone. Lastly, it is of course highly customizable and use Numix's wonderful icon set. With OpenBox, tint2 and ObSuite, you'll get a solid start for a light and beautiful custom desktop environment.
Have a look on the Gitlab page for screenshots and more info: