There are different frequency allocations for different operation purposes.
If we want to operate a device for Industrial, Scientific or/and Medical (ISM) purposes, then that device needs to operate in the ISM bands.
Freescale's KW products are designed to operate in these ISM bands.
The ISM equipment was restricted to specific frequency bands due to it generates electromagnetic interference that interrupts radio communications that make use of the same frequency band.
2.4GHz ISM band is UNIVERSAL, it means that all the devices with Industrial, Scientific or Medical purposes can operate in this frequency band in all the world.
For SubGHz ISM bands the frequency varies depending on the region. Refer to the picture below.
There are few frequency bands where a KW01 product can not operate in. From the KW01 datasheet, we can see that the lowest frequency operation is 290MHz and the highest frequency operation is 1020MHz.