Prestacycle UniBlock PRO Cassettes are machined from a single solid block of cold-forged Chrome Molybdenum alloy steel, then heat-treated, tumble-finished and electroplated for added durability, low-friction operation and longer service life. The UniBlock PRO cassettes feature ARC™ shifting tooth profile technology that provides the fastest, smoothest possible shifting to all systems while minimizing the impact to power delivery.

• Single block design offers 3D structure to optimize strength and distributes forces that allows Prestacycle to remove more unnecessary material making the ultra-light
• Single block design ensures more freehub engagement by reducing torsional loads for less freehub wear and insuring the lowest rolling resistance within the freehub
• ARC™ (Advanced Radial Curve™) Shifting Technology optimizes every single tooth pairing for exact-match pairings for both up-and-down shifts provide the highest possible speed and reliability in shifting... Even shifting under load is maximized
• Prestacycle UniBlock PRO's unique HG12 interface is compatible with all HG12, HG11 and HG10 Freehubs
• Wider inner and outer freehub teeth maintain engagement at all points in all gears to provide an overall increase in freehub contact
• Includes red anodized locknut for HG 12 and HG 11 freehub bodies
• HG 10 requires Prestacycle's HG 10 lockring (sold separately)