Record Store Day is gradually becoming a worldwide phenomenon. Soon the global affair could match the ranks of the those stateside holidays that some neglect, but the true enthusiasts ring in annually, like Arbor Day and Leif Erikson Day (no, really). So come this April 17th music fans can rejoice and metal fans can retreat to their bedrooms like it was September 18, 1970 to take solace in a limited Metallica/Black Sabbath joint release.

According to The Quietus the two forces will be putting out just 1,000 copies of this hand-numbered vinyl record. One side will contain a version of “Paranoid” with alternate lyrics, and the Metallica side will hold a remix of the St. Anger single “Frantic” as crafted by UNKLE.

April 17th is the day. To find your nearest independent record store click here, and for the list of other glorious Record Store Day releases you can click here. Still a little unclear on what RSD is? Let another icon of rock explain: