Liquid capacitive inclinometer
Liquid capacitive inclinometers are inclinometers (or clinometers) whose sensing elements are made with a liquid-filled differential capacitor; they sense the local direction of acceleration due to gravity (or movement). A capacitive inclinometer has a disc-like cavity that is partly filled with a dielectric liquid.
Source: Wikipedia — Liquid capacitive inclinometer (CC BY-SA 4.0)