The ones that I remember seeing on this forum were splice terminal taps. They were posted in a somewhat unrelated topic about GPS's, or sat radio, or heated grips, or some other electrical device.
The pics of them looked like they were molded black plastic; they looked different than other splice taps I have seen. I think the author said the splice terminals were weather-resistant without adding tape or shrink tube.
I remember thinking..."I won't forget where to reference these again."
Ooops, I forgot and can't find them now. Geez, I hate when that happens.