Originally Posted by eightbore
Ribless over unders of high quality are not new. The Boss ribless under over has been around for decades. The Browning Superposed lightweight ribless is out of the thirties. The Perazzi ribless over under is a new variation and I would like to own one. The Galazan Inverness ribless is fairly new, and rare. The Boss is the most desired and hard to locate, but the others can be found.

Here's "the Original" that all the imitation efforts are about:

https://www.gmackinlay.com/product/12g-over-under-by-boss-co-29-x-2-1-2-barrels/