Engineered by Sirris. Tuned by Zero. The Sirris F43 CMX fork for the Zero XB combines a race-built F43 chassis with a symmetrical closed-cartridge damper system and two independent sealed dampers. With wide-range XB-specific tuning, adjustable compression and rebound, and direct-fit integration, it delivers sharp handling, confident control, and elevated front-end performance for real trail riding.