Only 1.13 lbs! Looks like the duffel is made from Dyneema fiber. Very strong, I have a Tom Bihn Co-pilot bag made from that fabric. Just about right for United sizers though, 21.5/10.5/10.5 inches (United 22/14/9 inches).

Looks like Tom Bihn has a new travel pack, with a waist belt. https://www.tombihn.com/collections/travel-bags/products/heros-journey-travel-backpack?variant=31566549575

Almost 3 times heavier at 3 lbs.