Double Braids, sometimes called braid on braid, have a braided core within a braided outer jacket or cover. This creates a strong, durable, smooth-running line that is easy to handle. Double braids are used for the vast majority of all running rigging on sailboats including sheets, halyards and control lines for both cruising or racing. There are two types to consider: polyester double braids and high-tech double braids. Polyester double braids, found most commonly on recreational and cruising sailboats, have a polyester cover with polyester core. These are low maintenance, affordable, and long-lasting, while offering relatively low stretch and high working loads. For additional strength and minimal stretch, consider high-tech double braids. These lines typically feature a Dyneema or Spectra core (non-stretch) inside a polyester or polyester/dyneema blend cover for additional durability. They are more expensive but often the go to choice for high performance racing boats.