What Our Gearhead® Experts Are Saying:"Adding this Microspline freehub body to the H3 Plus trainer ensures you get the smooth, precise performance Shimano’s known for. Whether you’re powering through intervals or coasting to cool down, it’s a straightforward swap that makes a noticeable difference in drivetrain efficiency."When it comes to efficient, smooth riding on our trainers, the Shimano Microspline Freehub Body for the H3 Plus brings pro-level performance indoors. This freehub body seamlessly integrates with the Saris H3 Plus, so whether we’re sprinting, simulating climbs, or just pedaling at a steady pace, each pedal stroke is optimized for smoother, more reliable engagement. Shimano’s engineering means we can trust it to handle intense indoor training sessions without a hitch, giving us more power and precision in every ride.