8mm ropes are lighter, stronger and pack down smaller than the 11mm rope. 11mm ropes are optimized for use with the Ropeman 1 Ascender. 8mm ropes work with Kong Duck or Ropeman 4 Ascender.FACTORY SPLICED EYES ARE A BIG DEAL With this rope we were able to develop the world’s first commercially available 8mm rope with a factory spliced eye.