This is the Omer Threaded 7mm Shafts For E.T Roller Spearguns Features: 3 Sharkfin tabs Satin finish Available in 6.3mm, 6.5mm, 6.75mm, and 7mm Threaded shafts have 7mm threads Shafts integrating three shark-fins in place of traditional notches. The profile of the shark fins is thin resulting in better hydrodynamics and penetration through the fish. Each shark fin has a hole to attach the shooting line. The shafts come in a natural satin finish and come standard with a point design that increases penetration or threaded with 6mm threads.