Stuck in ebay once more I found this.

It was supposed to be a NISMO voltage/ground stabilizer that is supposed to "store electrical energy at all time to provide stable and sufficient electrical energy whenever there is a voltage drop across the supply when power needed from all parts in the car". Sounds like a good idea... but I begin to doubt that it is a NISMO part... He list the same item (same design and color) for honda/mitsu under differnt name brand company names. I had to email him about it. He at least admits they are knock offs with a fake company sticker for whatever car company he is selling it towards... But I thought you should all beware of this kind of thing. I don't even know if a voltage/ground stabilizer is a real part but ask before you consider ordering one.

 

So many of the Nismo products on Ebay are knockoffs, horrible ones at that

 

They (I don't know who exactly) DO make voltage stabilizers, I know they exist. As far as functionality and/or acutal benefits...I don't know. They exist though, to answer your question.