Comet Original AD-35M Antenna Mount Adapter UHF Female (SO-239) to 3/8-24 Threaded Antenna Mount

As advertised.

Good quality and heavy duty…

I have tested with a 6 meter Ham stick and a 1.25 meter antenna. You will find the SWR may not be friendly as the length of this changes things where adjustments on the antenna to shorten it cannot make up for the length this adds. That ground screw may help somewhat with a bit of wire connected to act as a counterpoise, but that is not much of a real world use. I have not tried it with Hamsticks that handle lower frequencies to say if it will work with them. Even with the 11 meter CB frequency range, adjustments to the antenna length (shorten) will probably be substantial. I did not give this product a low rating because of that concern. I found the product to be built well enough, considering a PL259 was never intended to be used as a mobile mount connector. (That is why there are 3/8 and NMO connectors.) I simply use this adapter when my vehicle is not moving.