I'll post test results when I get them. I can torture test one in my koi pond down to 4 feet deep.
That website seems to be one of those "Daily Deals" type of sites where if you don't jump on it right then they're gone the next day, or until sold out.
Whats strange is I just did a web search for 10 minutes or more, and cannot find them sold anywhere other than that Woot deal.
If they prove to work well, here is the company website:
http://www.safe-flare.com/index.html