It works perfectly to switch from my base radio to my cross band repeat radio. This way I can not forget to switch inputs to my one and only antenna.Unit works as directed. Only complaint is it turns off the connection for the other radio until you key it up. Then it will turn the antenna off on the other radio. So basically it will only RX on the last radio that transmitted. I understand that functionality. If you are using this in a situation where you have two radios that both need to rx all the time it will not work for that application. Other than that it works well as an automatic switch.Great replacement when running two marine radios on one antenna on the boat. Seamless switching between radios.Easy install and it works great.Just so you know, when you key your mic the antenna does switch over to that transceiver which means that the other transceiver does not receive anything (until you click on that mic, then the transceiver which was receiving does not anymore)... and if you think about it, it should work exactly like this... if it didn't then you'd be transmitting power from one radio into the other radio.... not good! It does constantly need 12 volts to switch over and I think once it's switched over you don't need power to hold it there....(there's a circuit board inside and it has a toggling relay switch on it) I'm going to try this on two ham radios.... I may burn this unit out because it's rated at 30 watts and my radio's put out 50.... I don't think the frequency range will be an issue... Marine Vhf frequencies are between 156 and 162 MHz and the Ham radio Vhf is 144 to 148 MHz and Uhf is 420 to 450 MHz, so the Marine frequencies are in between the Ham frequencies. I gave it a 4 star because nowhere does it state that you loose antenna connection at one radio when the mic is keyed at the other radio....this should be stated so the layman understands this.Adequate & Satisfactory. Item as described per need.