I don't want this thread to get too off topic, but the sling's stretch characteristics are solely dependant on the material it is made of. Nylon webbing and slings stretch and will reduce impact forces on anchors or gear. Dyneema/Spectra slings are considered static and have very little stretch, therefore they do not absorb impact forces like the nylon. This is a big reason why climbers should clip in to their anchor system using the rope or a nylon sling instead of something static. If you take a factor two fall onto your anchor with a static tie in, you can blow the entire system. This is easy to do when working above your anchor. 3 ft tie in, working 3 ft above the anchor, slip and take a 6 foot fall onto your anchor. That's a factor two and can have enough force to snap the slings.