This is the worlds most popular and most affordable VHF SWR/Wattmeter. It has a built-in Field strength Meter. Covers 144 and 220 MHz. Read forward and reflected power in 2 ranges - 30 or 300 Watts. Reads SWR from 144 thru 220Mhz. MFJ-812B also reads relative field strength from 1 to 220 MHz. Has binding post for field strength antenna. 2 color meter. Measures a super compact 4.5x2.25x3 inches.