MFJ-1922B

Digital Screwdriver Antenna Controller Tells you exactly where your antenna is positioned! Re-tune exactly -- fast, no more guessing. Super bright 5/8" high-intensity 4-digit LED display and precision micro-controller gives digital count range -999 to +999. On/off/reset switch for easy calibration. Compact 4W x 1.5H x 2D inches. Much more! Use 13.8VDC.