Epoxy resins are a group of synthetic resins used to make plastics and adhesives (e.g. Araldite). Most epoxies are two part liquid systems that when mixed with a hardener undergo a reaction that forms a solid un-fusible mass. Epoxies are known for their excellent adhesion, chemical resistance, and mechanical strength. They also provide high heat resistance and excellent electrical properties and are thus used extensively in the insulation of electrical and electronic devices. The number of epoxy materials is now extensive and includes adhesives and coatings.