Designed, produced and tested by mussel growers. Made from UV stabilized plastic, longer lasting, center pin is barbed, prevents it from falling off the sock, quickly and easily inserted, low labor. Holds mussels on rope, can increase your net harvest by up to 40%, recovering your capital investment in less than two years, discs have more surface area than pegs, will hold more mussels, reusable, will last for many grow-out cycles.