Yep. I've used them a lot with great success. Given the correct temperature, the fish can live for days in them.
There are a few precautions to using them (bags can not be doubled or touching one another; and they are puntured easily) so you must use them accordingly.
I suggest reading this site at least twice
Novalek - Kordon - Articles - The Amazing Kordon Breathing Bags For Shipping Fishes, Aquatic Invertebrates, and Aquatic Plants