These are the Team Losi Racing Silicone Shock Oils. Available in many weights for fine tuning of your shocks. Losi shock oil is made from 100% pure silicone oil and will not thin out in hot weather or thicken up in cold weather. The higher the weight number of the oil, the thicker the oil is. Losi shock oil is generally slightly thicker than Team Associated shock oil with the same 'weight' rating.