Maxima Racing Oils SERENE Dropper Post Fluid 16 fl ozMaxima Racing Oils SERENE Dropper Post Fluid 16 fl oz. High performance hydraulic fluid designed specifically for use in seat posts. The OEM recommended formulation reduces friction ensuring fast quiet action with minimal drag. High viscosity index formulation ensures consistent drop and return speeds under all conditions. Proprietary additive system protects seals minimizes wear and prevents corrosion improving performance throughout seat post life.