The MFJ-841 SWR-Watt Meter is designed for 2 meter handheld radios with a maximum power rating of 5 watts. The MFJ-841 uses your own antenna and plugs between it and your handheld radio. The MFJ-841 is used only with handheld 2 meter radios with a maximum rating of 5 watts. Do not attempt to use it for higher power ratings.
The wattmeter is used by connecting the MFJ-841 between your 2 meter handheld radio and antenna, switching to the PWR setting and keying up. Simply read the wattmeter. If by some reason the wattmeter is out of calibration, simply insert a known power source (2 meter only) and key up. Set the trimpot on the side (no need to open the case.) for the known power input.
The SWR meter is used by first setting the switch to SEN (sensitivity), keying up and adjusting the meter for maximum needle deflection. Key down and set the switch for SWR. Key up and read the SWR.