The bracket extends your mask farther from your face and glasses, preventing some fog, and alleviating that sense of suffocation.
After I use it for a full week I'll review it here. So far so good, in the day and a half I've used it.
Amazon and other outlets have more brands. My primary concerns in choosing this model and brand were: decent reviews, good design, and, most importantly, a very speedy delivery. My husband needed to have his on hand quickly. It’s not perfect but it's good enough if you tweak your mask.
You could possibly find a better model or price.
NPR posted some tips earlier in the pandemic: https://www.npr.org/2020/05/08/853009325/how-to-prevent-glasses-from-fogging-up-while-wearing-a-mask