Permatex Permanent Strength Red is a dual purpose, permanent-high strength threadlocker that is applied to fasteners 3/8″ to 1″ (10mm to 25mm) in size before assembly. Designed for securing parts that must withstand heavy shock, vibration, or extreme chemical or environmental conditions. Also used for sealing and securing cylindrical metal assemblies. Localized heating and hand tools are required to separate parts.