We normally use Xantech emitters and have never had problems not using the pigtails. We did however run out of stock and had to use Niles MF1 emitters and when I plugged them into the RP6, the smoke came out of the flasher and I can't get it to go back in. I haven't taken the time to see if the Niles units are slightly longer than Xantechs but I would gues they were just barely touching the 12v+ in the jack.