This is the Riffe Pole Spear Threaded Shaft Adapter Features: 17/4 stainless steel, heat treated and passivated 6mm thread both ends Made from 17/4 stainless steel, heat treated for hardness and passivated for corrosion resistance Used in combination with RIFFE's SUB-MINI Slip Tip or 3 prong Pinch Head (Tip Only) for RIFFE's Carbon Fiber Pole Spear