I am not David, but I do have 2 of his older model Outsaks.
Large Outsak (Older model than on site I believe):
And I also have a Outsak UL (again, I believe it is an older model too):
My UL sack measures 18 x 10 and weighs 4.1 oz, but again, I think that some changes may have been made to lighten this model up even more.
I will also say that my dealings with David have been exceptional. My packages always arrived within 3 days max and in the emails I have exchanged with him he has been very helpful. As well, he has some nice products too, IMO.
Hope this helps some.