Introducing the SRAM X-Sync Pulley Assembly - designed specifically to fit X01, X01DH, X1, GX 1x11, NX, Force CX1, Force 1, Rival 1, and Apex 1 Derailleurs. Expertly crafted with a wide-narrow pulley tooth profile, it guarantees secure chain retention. Plus, boasting stainless steel sealed cartridge bearings, it ensures smooth and reliable performance.