Polyester roundslings had their origins in the Scandinavian countries and began making their way to the Western Hemisphere in the mid-seventies. Polyester roundslings stretch at half the rate of nylon rigging straps. Polyester roundslings can be made in either an endless or eye and eye configuration. There is a unique advantage endless polyester roundslings have over eye and eye configuration slings. The endless configuration polyester roundsling is more versatile because the connection and load contact points can be rotated, enhancing sling service life. Another key advantage for polyester roundslings is that many slings can be made simultaneously, while nylon web slings have to be made individually, one at a time.
Due to the manufacturing efficiencies, polyester roundslings will generally be less expensive than nylon rigging straps. Because the body of polyester roundslings is comprised of multiple windings of polyester yarn, the sling body is soft and supple. The supple body prevents the polyester roundsling from locking to the load or binding at the point of choke when polyester round slings are used in a choker hitch. Polyester roundslings are color coded, but never rely upon color to determine roundsling strength. 15% of the male population is color blind and one producer’s red, polyester round sling may look similar to another’s orange polyester round sling.