Allen Brothers stopper balls are simple but highly useful rigging accessories designed to secure and manage control lines on sailboats. Made from durable, UV-stable injection-moulded polypropylene, these small plastic balls are fitted onto the end of rope or shock cord to act as a physical stop. They prevent lines from slipping through cam cleats, blocks, or deck fittings, while also providing a convenient grip point that makes pulling and handling ropes easier. Available in multiple sizes to suit different line diameters and offered in a variety of colours, Allen stopper balls are a versatile solution commonly used on halyards, control lines, and other running rigging systems where a reliable rope stop is required.