This finely braided Dyneema sleeve is used as cover for loops as well as to prevent chafe in high-wear areas on halyards and other lines. The black sleeve is black all the way through the fibers; the white can be dyed with Marlow’s Armourcoat rope dye, available HERE.
Highly chafe resistant due not only to the toughness of the fibers but to the fine 32 or 48-plait braid.