OS-S250R is their very own special blend of fully synthetic gear oil. It was formulated specifically for use in their OS Giken Super Lock series of LSD centres to achieve maximum performance & provide protection and durability under full race conditions. It is GL-5 Rated, 80W250 grade oil.
Type: FULL SYNTHETICSAE: 80W-250
API: GL-5
Flash point: 208℃
Viscosity: 320.5(40℃), 43.7(100℃)