HMC5883L(Or QMC5883L) Electronic Compass
In our Professional Kit, there exist two kinds of Compass module. One kind uses HMC5883L module, the other uses QMC5883L module. You will get one of them when you get the Professional Kit. They don't have too much difference. HMC5883L is made by Honeywell. but because the production is about to be stopped, so we use a similar compass module-QMC5883L instead. QMC5883L is made by a Chinese company, they get the production authorization of HMC5883L from Honeywell, and rename it QMC5883L. So QMC5883L and HMC5883L basically are the same, they shares the same hardware design. Just their register is a bit different. We only need to change the software a bit.
When you got the Professional Kit, please check which compass module you get based on the following picture. The HMC5883L has a label "L883"on it, while QMC5883L comes with "5883"