???? ?? ????? S2 R 68 ??? ??? ????? ??????? ? ?????? ??? ?? ???? ????? ????? ???. ??? ???? ?? ??? ??? ?????? ?????? ?? ????? ??????? ?????? ??? ??? ? ?? ???? ????? ?? ??? ?? ??smoothness ??? ????. Shell Corena S2 R68 : Superior Performance Under Tough Conditions Shell Corena S2 R 68 is a high-