Scuba Choice Spearfishing 12-Inch Stainless Steel Pole Spear Tip 3 Prong Barb Head Paralyzer Durable, Strong Stainless Steel material Total length: 12" long Female thread: 8mm in diameter Thread outside diameter: 14.2mm, Thread line: 1.25mm REPLACEMENT SPEAR HEAD ONLY FOR POLE SPEARS SOLD BY SCUBA-CHOICE