For years, gunsmiths have turned to Loctite for securing screws and other threaded parts on their projects. Each formula has unique features that make it perfect for various applications around the shop. Red Threadlocker (271) is a high strength threadlocker, which once applied requires special tools and extra effort to remove. This non-wicking formula is designed for permanent locking and sealing of threaded fastners. Prevents loosening and leakage from shock and vibration. Recommended for fasteners up to 1" in diameter.