For alpine climbers and mountaineers concerned about weight and packing space, Black Diamond presents the 7. 0 Dry Twin Rope. It weighs a little over four pounds all together, and it's Black Diamond's skinniest line, so it'll definitely pack better than the competition. Despite being light and thin, this climbing rope still features Black Diamond's durable 2 x 2 woven sheath and a dry treatment that excels UIAA's standards for water absorption. This dry treatment no only practically eliminates water absorption in the core, but also adds abrasion-resistance to the sheath.