The Cressi Bridle Beads are sold as a pair and are what is used to make up a bridle to insert in to the spear rubber. Without bridle beads it would be very difficult to load a gun as the beads are what stop the bridle from coming out of the rubber when loaded. They are pushed in to the gun rubber using some silicone spray and a T-tool and then tied off with constrictor cord. Beads can be reused but due to then being so cost affective, you would normally just purchase some more.
Cressi Quick Beads Pair