RCA and XLR shorting plugs??

The RCA Cardas are not shorting plugs. They simply cover the unused jack. They are a nice cosmetic addition that keeps dust out. I use them throughout multiple systems and have never noticed a sonic impact.

Music Direct sells a cheaper knock-off that is not as well made or as good looking, but still gets the "job" done.

I totally agree with Onhwy61. The Cardas plugs - which I also use extensively -- may produce a slight degree of quieting in my system, but that is no certainty. As for shorting plugs, best to check with the manufacturer(s) of your gear since not all components will respond well to their use.

They are great dust bunny stoppers for sure.

Actually, Cardas makes both the dust cover "caps" (which are described abvove) as well as genuine shorting plugs. You can buy both types frm Dedicated Audio (the shorting plugs are not actually listed on the website but they cary them). My Jeff Rowland Capri's manual specifically recommended using shorting plugs to avoid pops when switching sources.