With the solar eclipse less than a week away, interest in the astronomical phenomenon has taken off like a comet – a fact evidenced by the massive volumes of eclipse glasses that consumers and promotional product distributors are buying.

Nonetheless, authorities warn that knockoff glasses that won’t actually protect wearers’ eyes while eclipse-watching are in circulation, and it’s important for buyers to be sure that they have legitimate glasses before gazing spaceward. 

The issue came to light this week when Amazon announced that it was issuing refunds to customers who bought possibly counterfeit glasses. Amazon said the glasses in question “may not comply with industry standards,” further noting that it was removing certain solar glasses from its offerings “out of an abundance of caution.” The removed listings were not revealed publicly.

In order to prevent eye damage while directly viewing the eclipse, people must wear ultra-dark sunglasses that are made to specified standards that ensure ocular protection. The American Astronomical Society, an organization of professional astronomers, says would-be glasses buyers can rest easy that they’re getting the real deal by purchasing from a company on its list of reputable vendors, which focuses on retailers and manufacturers. The AAS further noted that companies not on the list could also have legitimate offerings. “If we don't list a supplier, that doesn't mean their products are unsafe — only that we have no knowledge of them or that we haven't convinced ourselves they are safe,” says AAS.

These quality shades will empower wearers to view the sun directly during the solar eclipse. 

So what to do if you have purchased glasses from a company not on the list? In the past, it might have been sufficient to check if the glasses were labelled as complying with international safety standards for filters for direct viewing of the sun. But amid eclipse mania, the marketplace now has eclipse glasses that are labeled as complying with International Organization for Standardization specifications even when they do not.

Still, the AAS has some helpful advice for personally testing glasses to see if they are safe:

“You shouldn't be able to see anything through a safe solar filter except the sun itself or something comparably bright, such as the sun reflected in a mirror, a sunglint off shiny metal, the hot filament of an unfrosted incandescent light bulb, a bright halogen light bulb…All such sources should appear quite dim through a solar viewer. If you can see lights of more ordinary brightness through your eclipse glasses or handheld viewer, and you're not sure the product came from a reputable vendor, it’s no good. Safe solar filters produce a view of the sun that is comfortably bright (like the full moon), in focus, and surrounded by dark sky. If you glance at the sun through your solar filter and find it uncomfortably bright, out of focus, and/or surrounded by a bright haze, it’s no good.”

Certainly, interest in eclipse glasses within the promotional products industry has been at fever pitch this summer. According to ASI research, eclipse-related searches in ESP, ASI’s product search database, have skyrocketed. Back in May, the word “eclipse” did not register in the top 1,000 ESP search terms. But for the month of July, “eclipse” was the seventh most searched term. That stellar performance followed a June in which “eclipse” was the 61^st ranked term in ESP. Most frequently, distributors are searching for “eclipse glasses,” says Nathaniel Kucsma, ASI’s director of marketing research. 

“This once in a lifetime opportunity brings together space, science and promo products,” Kucsma says. “Businesses that planned ahead now have the incredible opportunity to associate their brand with one of the biggest science events in history – an event that is captivating the entire nation.”

American Paper Optics (asi/35591), which is on AAS’s list of approved vendors, is among the companies capitalizing on the eclipse in a huge way. The Tennessee-based company expects to make 50 million paper and plastic eclipse glasses this year, according to the Associated Press. While the vast majority of American Paper Optics’ sales of eclipse glasses are at retail, the company has also produced a plethora of orders for promo products distributors whose customers want to tap into the marketing potential of the eclipse. “We’ve done a lot of orders,” CEO/President John Jerit told Counselor. “It’s 1,000 pieces here, 2,500 pieces there.”

Beyond eclipse glasses, there is an array of eclipse-related swag on offer in the broader marketplace, from businesses lucky enough to be along the path from Oregon to South Carolina where tourists are flocking to see a total eclipse, to online sellers looking to cash-in on eclipse enthusiasm. The online store at The Great American Eclipse, for example, has T-shirts, hats, can coolers, lanyards, lapel pins, temporary tattoos, luggage tags, viewing glasses, posters and more – most of all of which bears branding related to “The Great American Eclipse.” 

As CNBC reports, wine, jewelry, soap and toffee are among the other swag items for sale. And, in Oregon, where cannabis is legal, marijuana dispensaries are undertaking eclipse-related promotions. Items include pot-infused Eclipse S’mores kits.