If you’re gearing up to watch the solar eclipse on April 8, odds are you already know you need to wear adequate eye protection. It’s pretty easy to procure glasses designed for watching the solar eclipse– a lot of organizations are giving away glasses for free and deals are all over the internet.

Despite the ease of getting glasses, skygazers should be on the lookout for fake eclipse glasses. Real eclipse glasses are often designed with polyester film coated and coated in aluminum. Certified eclipse eyewear is designed to block all visible, and infrared light. Solar eclipse glasses must be from a vendor approved by the American Astronomical Society.

If you order a pair of solar eclipse glasses online and want to ensure their safety, there are a few things you can do, according to the Washington Post.

• Test your glasses at home: Try putting your solar eclipse glasses on inside around a bright light. If it seems like a lot of light is coming in, they probably aren’t valid.
• Cross-reference the glasses you ordered with the list of trusted and well-known manufacturers and vendors. The American Astronomical Society has a list on its site.

HOW SHOULD YOU PROPERLY USE ECLIPSE GLASSES?

Here are instructions on how to properly use eclipse glasses, according to the Detriot Free Press:

• Before viewing the eclipse, the American Astronomical Society recommends inspecting the glasses and discarding them if they are scratched, punctured, torn, or otherwise damaged.
• Wear eclipse eyewear over your normal glasses.
• Cover your eyes before you look at the sun, and wait to take the glasses off until after you’ve turned away from the sun.
• Do not use an unfiltered camera, telescope or binoculars even if you’re wearing proper eyewear.