Our bestselling friction hitch and autoblock has been redesigned with a stronger aramid fiber.The 6.8 mm HollowBlock2 is made of 100% TechnoraA(R) fiber for increased abrasion resistance and improved durability. It&';s gripping ability comes from the unique hollow-braid construction, for use as a prusik or Klemheist knot on ropes 7 mm or larger. Key Benefits a 100% Technora Construction a Significant increase in durability and performance a Same function and grip as the original