There’s a total solar eclipse coming across much of the country on Aug. 21, which will be amazing to watch. However, use caution, and make sure not to risk your eyesight to see it. Not only should you wear special eclipse-viewing glasses when you look at the sun, but you should make sure that those glasses aren’t counterfeit.
Counterfeit eclipse glasses are a thing?
Yes, there’s an online market for counterfeit eclipse glasses, and it’s a very robust one. In response to the demand for eclipse glasses, companies have popped up to meet that demand.
The glasses are essential because they let us safely look at the sun while it’s in partial eclipse, before the moon moves in front of it fully.
You can find hundreds of listings on Amazon, but just because a company says that they’re selling eclipse glasses, or throw around the correct ISO number, that doesn’t mean their products are safe.
A writer for Quartz bought some glasses on Amazon, and later learned that they were counterfeit, even though they claimed to be certified.
NASA has put the word out about these fake lens slingers, and named a few companies that are trustworthy providers of lenses or glasses. Here’s what you need to look for:
• The glasses should have certification information, with a designated ISO 12312-2 international standard.
• The actual manufacturer’s name and address should be printed somewhere on the glasses.
• Don’t use glasses that are wrinkled, scratched, or more than three years old.
• Don’t use regular sunglasses, no matter how dark they are.
NASA recommends buying glasses from from one of five manufacturers:
• American Paper Optics
• Baader Planetarium (AstroSolar Silver/Gold film only)
• Rainbow Symphony
• Thousand Oaks Optical
• TSE 17
This is not a money grab on the part of these manufacturers. “There are a zillion companies putting out the same product and they all have different names,” a representative of Rainbow Symphony told Quartz. “And this isn’t because I don’t want competition in the marketplace. We’re oversold and on backorder. It’s not my motive to keep competitors out of the market.”
Unfortunately, just looking for those five names on Amazon isn’t enough, since the counterfeiters are using names of the approved companies. NASA says that it will release more information before the eclipse, incuding the names of more approved vendors.
So far, experts haven’t found any counterfeit glasses that are inadequate or harmful, but that doesn’t mean that there aren’t any out there. It’s one thing to buy sketchy fidget spinners, but do you really want to risk your eyesight?

Editor's Note: This article originally appeared on Consumerist.