I know you didn't ask this, but:
4 years ago I got one of the UV coated jobs (from a mail order company in the US) for trekking in Nepal and it worked great for about 2 weeks, then became impossible to extend, the sections were frozen. The mfgr sent another, so their service is great, but after even less time using it stateside, maybe 2 or 3 days for sun protection, the replacement was useless as well. The problem is that sweat, which I have a lot of, seems to corrode the collapsible shaft sections and basically weld them together, and it happens pretty quickly. I've tried rinsing it after hikes etc, but that doesn't solve the problem. I think the product just isn't suitable for use as a sun umbrella because of this design issue, at least for anybody who sweats, and that's what I got it for. I'm back to my carbon fiber Golite.
Good luck if you do decide to get one.