XTR Racing Ronnefalk Pure Silicone Diff Oil 4000 CST Edition V2 100ml (3.4 oz). Part number XTR4K.
XTR silicone oils are produced under strict control in XTR's laboratory and were tested and developed by XTR's World Champion drivers. They were tested in extreme temperatures for durability and stability, and XTR guarantees the best performance from the start to the end of the race.
