I paid $35 for this thing last year and was pretty disappointed when I got it. It feels disposable and not at all like the premium rubber pouches sold by people like Magpul. But a year later and I have to admit – while these things are very light and thin, they are durable as hell and my pouch is still 100% waterproof. I have no idea why the material used is so unbreakable, but I think the biggest reason for its waterproofing is the zipper. It’s really great.
In any case, they are expensive… but damn do these things work well.