This Screw-Tight Round Insulator is made of durable high quality PP with smooth surface, without thorns, not easy to frayAllow electric fence wire, poly wire, poly rope to be free running up to 5mmDurable high quality PP material for high strength, UV and weather resistant, non-deformation, harmless to people and livestock, can be your helpful tool for yard, farm or pastureImpact resistant plastic, sturdy, can be used for a long time