The Antal DV Jammer for D12mm Lines Standard is a powerful and reliable solution for controlling thicker control lines (12mm) on sailboats. Its low-friction design, "Double V-Grip" system for secure line holding, and compatibility with D12mm lines make it a popular choice for sheet control of very large sails, halyard control for mainsails or very large sails in some cases, and other control line applications requiring additional strength and reliable grip for thicker lines.