Hi, I'm not educated on these things. I basically go out on the weekends and buy whatever I think will sell on ebay for a little extra cash. I listed a Black Cat model JB-74A (I found one of these online and it says it's an amplifier) and a unit that just says 150 HL (I could tell it was something to do with vintage ham or cb because of the plugs on the back). I listed them on ebay, and the next morning they had been removed for "violation of policy". I don't understand why.