Single braids - 100% Dyneeema: Used primarily for applications where the line is spliced on both ends. Not meant to be cleated unless a cover has been added. Can be difficult to hold by hand.
Single Braids - blends: These are lines that have other filler materials added to them to increase size and grip making them easy to hold with the hand. They absorbed little water and remain light and free running. These lines work well for mainsheets and some control lines.
Double Braids - Polyester jackets with coated Dyneema cores: These lines are used with the cover on or partially removed (stripped and buried). The coating on the core helps to keep the weave compact when not under load. Partially stripping the cover removes weight from racing halyards, sheets and controls when weight is critical. In some cases, other materials have been added to the polyester in the jacket like Technora or Cordura to increase abrasion resistance.
Polypropylene covered with uncoated Dyneema cores: While the cover material is the least durable, it is light weight and floats. The Dyneema core provide low stretch performance. These lines are best suited for spinnaker sheets on dinghies and small keelboats, as they stay light and won’t collapse the spinnaker in light wind sailing. Often the cover can be stripped to further reduce weight. Polypropylene covers do not hold up well when highly loaded on winches, and can even melt under extreme loads when easing.
Polypropylene covered with coated Dyneema cores: While Polypropylene is the least durable cover, it is light weight and floats. The core eliminates stretch. These lines are best suited for spinnaker sheets on dinghies and small keelboats that stay light and don’t collapse the spinnaker in light wind sailing. Note that Polypropylene covers do not hold up well when highly loaded on winches, and can even melt under extreme loads when easing.
Small diameter double braids: These are generally a 100% Spectra core with Polyester (or blended jackets) used in dinghy sailboat applications where extremely low stretch is required and hard wearing jackets can hold up well to abrasion and cleating.