12 mm (1/2") 'SuperSpeed' is quality double braid with a HMPE core often know by the trade names Spectra and Dyneema. The cover is high quality polyester. Made by Southern Ropes. Break load 13200 lb. This line have a vastly superior breaking strength and considerable less stretch that double braid polyester lines. Ideal for blue water cruiser and club racers halyards, etc.