Our liquid gauge line is a high quality line. The glycerine filling helps dampen the effects of pulsation and vibration, while also perpetually lubricating the movement (and keeping contaminates such as dirt away from all moving parts) which will extend the life of the gauge. These gauges have been specifically designed with original equipment manufacturers in mind and are typically used on hydraulic & pneumatic systems as well as any commercial or industrial application noncorrosive tomore brass and bronze wetted parts where glycerine filling is suitable for use. less