This is the Cressi Sub Shooting Line Competition Monofilament Nylon Thread for spearfishing Features: Cressi Competition Nylon Shooting Line Diameters: 1.60 or 1.80 mm (1/16 or 5/64") Extremely Hydrodynamic Profile Very Low Drag for Lightning Fast Shaft Speed Smooth Outer Skin Pulls through Fish with Minimal Tearing of Flesh Stainless Steel Crimping Sleeves for Corrosion Resistance Monofilament Design for Superior Strength and Abrasion Resistance Cressi&';s High Strength Monofilament Nylon Shooting Line has a 1.60 or 1.80 mm (1/16" or 5/64") diameter, giving it an Extremely Hydrodynamic Profile with very Low Drag for Lightning Fast Shaft Speed. "