As you can see on the FMuser site, there is a CZH unit (black case) pictured with the silver units.
These units can be set to operate in two power modes. 1.5w and 5w (typical 7w). These can also be set so that if the power goes out and returns, you dont have to re-set your operating frequency. Simply program the unit's upper and lower frequency range to your operating freq.
1. Hold power button on while plugging the power source into the power jack.
2. Display will show either an "L" or an "H". L for low power, H for high power. Use the + or - keys to set, push the power button to go to the next setup sequence...frequency range.
3. The unit will start at its upper frequency setting from the factory. *NOTE: These units CAN transmit well above 108 Mhz and well below 88 Mhz so be careful!! Set the unit's upper frequency limit, then push the power button to go to the low frequency limit.
4. Set the low frequency limit and push the power button. The unit will store the settings and power off.
During these setup stages, the unit will not be transmitting, however it is always safe to attach a dummy load to the output when going into the setup/power modes.
They are great little units with excellent performance for the price.