MFJ-212 Tunes up your antenna tuner without transmitting a single milliwatt! No power. Precisely tune your antenna tuner for a 1:1 SWR -- no additional "tweaking" needed. Avoids overheating/arcing caused by high SWR and long tune-ups. MFJ's
RF*Guard bypasses the MFJ-212 to prevent damage. Handles up to 300 Watts. Works with all radios 160-6 Meters. 3 1/3 x 1 1/4 x 4 in. 9-12 VDC or 110 VAC with MFJ-1312D.