The MFJ 259B is an HF/VHF SWR analyzer. This handy test instrument connects to an antenna feedpoint, and generates a low level RF signal indicated by the built-in frequency counter. The 259 features a tuning control which allows sweeping the output frequency to find minimum SWR and specific feedpoint resistance simultaneously. It operates from 1.8-170 MHz continuous, and uses 10 AA batteries; measures 6.8"H x 4"W x 2.5"D.