Solid canvas , quality zips and the one I have carries my 127mm f8 Istar well , and the price is great .
Way solid'r than the bags shown in your link
I also noticed the 'Swag Bags' ( 1000mm long x 400mm square ) and these will take up to probably a C11 SCT and 8 -10 inch Newt easily and only about $30 , the brand is
'BOAB' outdoor .
I will post a photo of mine tomorrow if I find the time .
I got mine fro Rays Camping as I said , take a look in the tent pole section .
Brian.