OS Giken (founded by Masaharu Okazaki in the early 1970s in Okayama, Japan) has earned legendary status crafting race-grade drivetrain components designed for performance and durability. Their U.S. distributor, OS Giken USA, offers JDM-expertise through clutches, gears, Super Lock LSDs, and tuning accessories—each 100% manufactured and assembled in Japan under strict quality-control standards.

The Super Lock LSD, born from four-plus years of R&D, supports up to 28 clutch plates and delivers smooth, progressive full locking without chatter—engineered for repeatable track performance. Their twin‑plate clutches and flywheel combos are precision-machined, increasing drivetrain efficiency and throttle response—built as complete systems inside exact tolerances. 

OS Giken’s passion for engineering extends to custom projects: RB26 stroker kits, TC24 L‑series twin‑cam heads, sequential gearboxes, and more—displayed globally and respected by enthusiasts and pro race teams. For serious tuners seeking drivetrain strength, reliability, and Japanese craftsmanship, OS Giken delivers pedigree-backed performance with world-class support.