PVC, also known as polyvinyl chloride, is a synthetic plastic polymer with a rigid structure. PVC resists corrosion and most chemicals. CPVC is similar to PVC, but has been chlorinated. It is similar to PVC in chemical resistance, but is more ductile, and is capable of withstanding higher temperatures. Glass-Filled Nylon is similar to nylon, with increased strength and rigidity. Nylon is suitable for use with oil and high-pressure air/gasses, but is not suited for strong oxidizing agents. Polypropylene is a durable and flexible thermoplastic polymer. Polypropylene valves are often lightweight and easy to install, and are also resistant to corrosion. PTFE is best known as the material used to coat non-stick pans. It has an extremely high melting point and can withstand high temperatures.