... flexibility,easy to use,light weight,and long service.Product:stringing pulley blocks;stringing blocks.Usage:Protect the cable and conductor from fricting ... ,OPGW,ADSS, communicatio lines.c. The sheave of the pulley blocks are made from higth strength MC nylon,or aluminum ... ones are mounted on ball bearings.Remarks:All kinds of pulley blocks can be manufactured according to the customers's requirements ...