I got mine from a lampwork bead store that had a teaching studio that was closing the teaching area some half dozen years ago and had them in a Craigs List ad.
I sent them a check and they sent it to me after the check cleared the bank.
Here are a pair of listings I found by doing a search of LE posts:
Good luck
https://theblastshield.net/
http://www.phillips-safety.com/glass...nd-visors.html