Twin-Path® slings have the Fiber Optic inspection system. The condition of the internal core yarn can be inspected just by checking the continuity of the fiber optic cable. If crushing or cutting, heat or chemical damage, has occurred then the damage to the fiber optic cable will destroy its ability to transmit light from one end to the other giving the inspector a reason to remove the sling from service and send it in for repair evaluation. The fiber optic cable will conduct light using natural, overhead or flashlight sources. The inspector simply covers and removes his finger from one end and watches the other end for blinking which indicates that the sling is OK to use for another lift.

US Patent #4,850,629, #5,651,572
CN #1,280,458, #2,195,393
Italy #97300367.6
Japan # 2929431
Australia # 707924