Coupling Banana Plugs

You can stack most banana plugs. Check out Parts Express.
https://www.parts-express.com/parts-express-gold-dual-banana-plug-black--091-334

Yes, but the cables I am using already have banana's attached on each end. So stacking is not an option.

What I seek is a coupler. Sort of like a RCA coupler that is used to connect 2 RCA's together, but made for banana's.

My DIY version does fit the bill, but I am surprised that there really is no commercially made product.

"04-20-15: Denman
Monster used to have a model banana plug called the Exterminator that had a hole on its rear to piggyback another banana plug.I still have some,but they aren't for sale."

They still make connectors like that but they won't work in this case. Both ends need to be female.

Googling "banana plug coupler," with the quotes, returns what appear to be a number of promising choices. The most efficient way to peruse them, amidst a number of irrelevant results that are also returned, is probably via the Google Images link.

Regards,
-- Al

Thanks Al, The one highlighted in yellow is what my DIY looks like.
It seems all that would work on the image link that you have provided is either in China or the UK. Nothing in the USA.