In the ’80s, novelty phones were all the rage. They were often wacky (e.g., DJ Tanner’s plump red lips phone, the hamburger phone), tied to cartoons or toys (e.g., Garfield, Pac-Man) or see-through. However, perhaps the granddaddy of them all was the football phone, the free gift given to anyone who plunked down the bucks for a subscription to Sports Illustrated.

How did this cumbersome and ridiculous-looking item become a must-have? That’s the question a new Rolling Stone explainer, “The Funky Little Football Phone That Sold A Million Magazines,” answers. As it turns out, the football was the brainchild of then-SI marketing manager Martin Shampaine, who had the idea one lunch break while he was musing about how to get people to subscribe. A direct-mail test of the premium was wildly successful; next, the company spent months overseeing production and manufacturing to ensure every aspect of the phone was just right.

To promote this and other premiums, including an even-more-ridiculous sneaker phone and highlight-reel VHS cassettes, SI produced infamous cable TV ads, including one featuring Mad Men’s John Slattery. Between these commercials, free gifts, and the kitschy allure of the oblong phone, the magazine signed up an astonishing 1.6 million new subscribers between 1986 and 1991.