I had to hack the web site's source code to get to this :) but here's the full pic for further forensics https://images-prod.gothamist.com/images/IMG_0113.2e16d

I had to hack the web site's source code to get to this :) but here's the full pic for further forensics https://images-prod.gothamist.com/images/IMG_0113.2e16d0ba.fill-1400x934.jpg https://images-prod.gothamist.com/images/IMG_0113.2e16d0ba.f... I would say you are right that the zips are stainless steel. My guess is they could still snap easily with a lot of wind but actually I don't know how much load they can take.