Passive A/B box negates the need for yet another PS, but its yet another box , so hmmm... i'm weighing it up.
The Ebay item is actually on Amazon, but i hear what you say. I cant tell whether they messed up the description ( it's a Chinese adaptor ) or not. Even if not, the descripton is still odd.
As i mentioned, it simply looks like 2 mono in 1 mono out, yet they mention stereo but i see nothing that makes that jack / adaptor stereo. Surely mono in is mono out ?