Hardened stainless steel with plastic 16mm threaded caps. 16mm is standard and will work with most threaded bands in the market today like Mares, OMER, Salvimar, Pathos, etc. High resistance, for the ability to withstand excessive force. Articulated system to make loading easier. Thicker arms will provide long-term use. A flat hook will hold better on notched spear shafts.