Chosen for its balance of suppleness vs torsional rigidity. 6mm and 7mm sizes are appropriate for personal use such as Purcell Prusiks. 8mm is appropriate for general Prusik use. 8mm and 9mm are good for use as load release hitches and utility cords. 

6mm (strength 6.8kN), 7mm (strength 9.3kN), 8mm (strength14.0kN),  9mm (strength16.2kN)

Full Spool