These Ball knobs are constructed using a Duroplast (Phenolic PF), which gives great heat and cold resistance as well as Oil and grease resistance. This makes these a strong and durable part. Especially suited for mechanical function components and mechanical engineering, these knobs have many more uses, from cabinet doors to wheel turning these knobs are a great addition or replacement to your old components. Features and Benefit: Temperature resistant -20 C to 180 C so can be used in high temperature machinery or in cold environment areas Resistant to Oil, greases, weak Acids, Petrol and Alcohol for better and wider range of uses Zinc plated Steel bushing provides that added resistance to corrosion from things such as petrol or alcohol Typical Applications: Mechanical engineering Thermally Insulating Operating Elements Cabinet and storage solutions Automotive solutions