The Cressi Euro Adaptor Brass Set is used as bridal beads for any Euro Speargun (14 thread 16 mm) with a threaded muzzle like Cressi and Omer.
These two high quality, brass Euro adapters will pay for themselves after the second set of rubbers you make with them. The small ball is placed inside the rubber as far as it can go. Then you use constrictor cord to tie around the end of the rubber to keep the balls in place. Then the screw end is screwed into the gun (specific to certain guns).
If you have the suitable speargun this option is very popular, as you can reuse the brass adaptors over and over again. You then will put a bridal in the other end of the rubbers to create a finished gun rubber.
Why use plastic adaptors when you can use brass ones that will last and last.
Set of two Euro brass adaptors.