Closures or Lace extensions are made from a nylon mesh material formed into a cap that is then hand ventilated by knotting single strands of hair into the tiny openings of the cap form, giving the hair a more natural, realistic flow than conventional extensions. Closures do not run temple to temple. Instead they are placed in the horseshoe area at the top of a weave to close off the style.(Hence the name closure). These extension units can be woven in or attached to the hairline with special adhesives.