Anaerobic adhesives remain liquid until isolated from oxygen in the presence of metal ions, such as copper or iron. When an anaerobic adhesive is sealed between a nut and a bolt on a threaded assembly, it rapidly "cures" or hardens to form a tough cross-linked plastic that will bond quite well to many metals. Anaerobic applications differ widely with each applications requiring high shear strengths and resistance to temperatures as high as 230°C (445°F).