So I got my Ultimate breather bags in yesterday. They are a little larger than Kordons, and printed in green ink.
It's true the bags do not have side seams, and the bottom looks heat sealed. Very well, I may add.
The feel of them is different as well. The Kordons feel rubbery and have some stretch to them when tying a knot. These feel more like poly. No rubber feel, no stretch. So *could* be a different manufacture altogether. Still is supposed to be O2 in and CO2 out, though. People who like poly better would definitely like the feel of these bags.
I'm doing a trade with Shrimpo this week and testing the bag, so we'll see how they hold up for the aquatics.