The diameter is 12 mm. The spiral structure has good heat dissipation performance and low friction. Especially suitable for rope training. Traction force 28kn; use load 0.5kn, weight (100m) 9.5kg-9.8kg; melting point 215 degrees; expansion and contraction rate within 36% (initial load 18kgf) (mainly used for fire force training, competition, rescue. It is currently used in fire New products highly recommended by the Bureau.)