J Mascis' main guitar is a sunburst ’63 Fender Jazzmaster with its original neck and pickups. He replaced the pickup covers and knobs, and added a Tune-o-matic-style bridge. All of his guitars have been outfitted with jumbo frets and he uses Ernie Ball Cobalt wound strings and RPS (with a reinforced ball end) unwounds (.010–.046), and purple Dunlop Tortex (1.14 mm) picks.