Replacement rivet-type master link for the EK Chains ZVX3 chains. Sold individually. Note: Actual color may differ from image. Back in 1974, EK Chains introduced the world's first sealed O-ring chain. Quality is an obsession at EK Chains. In 1997, the company was certified to ISO 9001 quality management standards. This certification recognizes the high standards of the quality assurance system and reinforces EK's guarantee of safety and precision in every product they sell. Research and development at EK Chain has always focused on creating technological breakthroughs and developing original ideas, and a relentless commitment to innovation continues to drive everything they do.