An Introduction to Vis-Lok Vis-Lok stainless-steel twin ferrule compression fittings are rapidly becoming the industry standard for reliability and strength. In the realm of twin ferrule compression fittings, the qualities of robustness, strength, reliability and performance are of paramount importance. These critical attributes ensure the safety and integrity of piping systems, providing a dependable foundation for sustained operations under all conditions. This is especially important in industries and applications where failure can result in significant hazards. Twin ferrule fittings such as Vis-Lok are designed to withstand the rigours of extreme conditions, providing reliable, secure, leak-proof connections that will maintain system efficiency and minimise operational downtime.