Leave it to greedy assholes who want to get their disfunctional products on the market and not care for people's safety.
Nasa reccomended brands are:
American Paper Optics
Baader Planetarium (AstroSolar Silver/Gold film only)
Rainbow Symphony
Thousand Oaks Optical
TSE 17

There should be a logo that says ISO as well as the numbers 12312-2 somewhere on the glasses.