Compass 2 click is a magnetometer based on a high sensitivity Hall effect sensor.
Chinese people from two thousand years ago were the first to use compasses. It's a tool as old civilization, or at least as old as sea-fairing.
Mankind kept improving on the idea, but the working principle is still the same.
We went from lodestone to silicon, and then finally to click boards ;). Compass 2 click is an improvement to its predecessor in that it has a configurable interface: you can set the output through SPI or I2C. This is convenient for those who use multiple click boards on boards with MCUs that have a limited number of peripherals.
Other than that, it has fairly standard precision rates. The internal ADC can be set to be either 12 or 16 bit.