4mm Edelrid Tagline can be used as a pull cord for rappeling a knot blocked rope, saving you from having to hike an entire 2nd rope. You want your pull cord to be grabby and light. Here are the stats on 4mm super static cords 4mm Edelrid Tagline: $1.07 per foot or $240 per 70m. 10g/m or 1.54lbs per 70m 4mm Polyester (PES) cord: $0.28 per foot or $64 per 70m. 16g/m or 2.47lbs per 70m 4mm HMPE: $1.17 per foot or $266 per 70M. 8g/m or 1.23lbs per 70m Get all your tag lines at https://hownot2.com/