The Larc Buckle is a transformation device that Natsumi Miwa uses to become Kamen Rider Larc. Along with Glaive Buckle and Lance Buckle, this belt is created with similar designs to Leangle Buckle. Its designed specifically for compatibility with the A: "Change Kerberos" Rouse Card. This Rider System model utilizes the "Open Up" mechanism, to scan the Category-Ace Rouse Card; producing a transformation screen that attracts to the Rider. Coincidentally, the transformation screen itself can act as a deflective wall against assaults.