Bluetooth Power Classes VS Working Range

Raytac Corporation
A BT4.1 & BT4.2 module maker based on Nordic nRF51 & nRF52 solution 
(nRF51822 & nRF51422 & nRF52832 & nRF51802)
Tel: +886.2.3234.0208
There is a frequent question comes up from people!
What is the Bluetooth Power Classes? What is Class 1 and what is Class 2?
What the relationship Power Classes related to working range?
Here, there is a simple chart can help everyone to have an easy understanding!
Information quoted form Bluetooth Organization (SIG)
Now, it is obviously to know why Raytac’s module is superior!