This is the Koah Reef Floatline 5/16in Diameter 450lb Dyneema CoreFeatures: 450lb internal dyneema core stainless steel plugs and hardware 20% stretch outside diameter of 5/16in The Floatline is the hi-vis, low drag connection between your speargun and the Float. The Koah Floatline is made from the highest grade materials with a dyneema core. It comes with stainless steel plugs and hardware and is made from UV stable, high visibility tubing. The floatline also has a 20% stretch to handle the initial shock from the fish as it runs.REEF- which contains a 450lb internal dyneema core and has a lower outside diameter of 5/16 for lower drag.