It was in the mid-seventies that polyester round sling made their way to the Western Hemisphere from Scandinavia. Round sling made of polyester stretch half as fast as nylon rigging straps. Roundslings made from polyester are available in both endless and eye-and-eye configurations. The advantages of endless polyester round sling over eye and eye configuration slings are unique. The endless configuration polyester round sling is more versatile due to its rotating connection and load contact points, enhancing its service life. Polyester round sling also have the advantage of being able to be made simultaneously, whereas nylon web slings have to be made individually, one at a time.

Polyester round sling will generally be cheaper than nylon rigging straps because of the manufacturing efficiencies. Multiple windings of polyester yarn make the body of polyester round sling soft and supple. When polyester round slings are used in a choker hitch, the supple body prevents the polyester round sling from locking or binding at the point of choke. Roundlings made of polyester are color-coded, but their strength cannot be determined by their color.

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