[amsat-bb] mfj 270 lightning surge protector

hi all, i know this is off topic hope no one minds, but on the mfj 270 there is a in and a out, does anyone have one of these and know if the rig goes to the in or does the antenna? I wrote mfj but prob will take days to hear back from them and am in kind of a hurry, so trying here. thank you all, kc8gkf