The 6.5mm SEAC shaft Shark stays strong as it leaves your Speargun thanks to its 17-4 pH stainless steel construction, which is Heat-Treated to harden the steel to create an outstanding combination of high strength and corrosion resistance. It also features three high-resistance Shark fins on the shaft. Founded in Italy in 1971, SEAC proudly continues to take the lead in producing high-quality diving gear and ensures that each and every product is individually verified and tested.