Dual Use Centerlock FeaturesShallow screw channel for adjustable fied postioning.Deep screw channel for free-sliding between stops or for break-away rigging.Patented O-ring insert design.Tapered clamping surfaces for maximum hold on even very fine leaders.Textured out surfaces for grip and easy identifications of half to rotate.Razor cut line retention slits prevent line from twisting while tightening.All Part manufactured with eco-friendly materials.Mix and match color options.ECO FRIENDLYWe believe in keeping our waterways as clean as possible. We redesigned our popular strike indicators with eco friendly foam so those indicators that end up floating away for any reason will break down over time.Not to be confused with water soluble: Air-Lock eco friendly Strike Indicators will not dissolve or be compromised in any way during normal use.Biodegrading happens when the material is left in the elements: mud, water, mulch, compost, etc. over a long period of time.WARNING: Cancer and Reproductive Harm -www.P65Warnings.ca.gov