The patented design changes to the body and edge of our new Tuff-Edge III translates to a softer web with increased abrasion and edge-cut resistance. Introducing the Edge Damage Limit (EDL) out-of service marker. The EDL tool both simplifies the inspection process and also extends the life of the web slings, saving you money. Whenever sling damage is concentrated along the edge of the webbing, the sling may continue to remain in service until the damage has reached the EDL black line marker, assuming the sling is otherwise in good operating condition.