The O-Flex has a high tech core specially designed for indoor climbers. The core cables are wound together in a helix pattern to form a core that retains the ropes roundness better than traditional climbing ropes. This is important to rope longevity in indoor climbing environments where top-rope is the norm. In addition to the special core, the sheath is thick for long wear. The new 9.8mm size is superb for clipping biners. Super smooth HD sheath weave reduces rope drag and increases rope life in gyms. Pre cut 30m option. O-Flex also makes a great outdoor rope.