(Image: YouTube screen grab via White Castle)

Monday, May 15, is National Slider Day. In observance of the day, White Castle, which invented the slider — not to mention the food holiday itself — is giving away free sliders to all comers. The lone requirement for cashing in on your gratis burger is to display the coupon found on the chain’s website, which has been reprinted below for your convenience. In a rarity for promotional giveaways, no purchase is necessary.

There are three White Castle locations in Manhattan — one at 103rd Street and First Avenue, one on Eighth Avenue at 37th Street, and one on Adam Clayton Powell Jr. Boulevard between 124th and 125th Streets. The boroughs fairly teem with the restaurant.