In most applications the stem and float are immersed in the liquid being sensed. It is important to match the stem and float for a given liquid. Polypropylene is typically used for water and mild acids. Polyamide is generally used for oil, gasoline, and brake fluid. Nitrile butadiene rubber (NBR) is primarily use for the float material. The NBR offers much better resistance to oil, fuel and has the ability to operate reliably in high temperature applications. NBR also has excellent features over a broad range, including an excellent stable buoyancy ranging from -55°C to 180°C.