Polyester sheath braided over a double twist nylon cable core. The new ProTac rope is slightly smaller diameter than standard 7/16 Assaultline because of the use of a greater number of smaller diameter sheath yarns. 50/50 ratio of sheath to core ensures good abrasion resistance. Much smoother running in descent control devices. Originally developed for the FBI training center in Quantico, Virginia, this new construction technique has been recognized in the tactical community as the best all around rappel rope available today. Certified to NFPA 1983/2006 edition. Price is per foot.