Ocean Rhino and A.B. Biller Style Spear Shafts Made From Heat Treated Aviation Grade 5/16 Spring Stainless Steel. 6MM Threaded End Shafts. Fits All A.B. Biller, Spearfishing Specialties & Sea Hornet Spear Guns. We only use the best American Heat Treated Stainless Steel! 6mm threaded tips fit most all standard spear Tips & Prongers See Description for Gun sizes & fitting