Castrol Synthetic Fork Oil is a totally synthetic suspension liquid designed to offer exceptional damping properties for all suspension on and off the road. Its synthetic formula and its natural high viscosity index are able to offer great performance that counteracts the loss of damping at different temperatures. CASTROL Synthetic Fork Oil allows a quick release of air and constancy of damping in extremely difficult conditions such as in competitions. CASTROL Synthetic Fork Oil prevents suspension "locking" which therefore works perfectly and progressively