U bolt missing
This MFJ 2-position remote antenna switch uses a single coaxial feedline to feed two antennas, DC power and control signals — no power or control cable needed
It’s perfect for switching from HF to VHF — no more unplugging coaxial lines from your antennas just to switch frequency — a quick switch does it for you
MFJ-4712 covers 1.8 MHz-150 MHz and handles 1500 Watts. Impedance is 50-75 Ohms
The compact 4 W x 2 5/8 H x 1 1/2 D inch Outside Switch Box is fully enclosed and weather protected. It also has three quality Teflon(R) SO-239 connectors for transmitter, antenna one and antenna two.