Another neat Poly plastic insulator co. is the Hendrix Wire & Cable Co. Inc of Milford, NH. Founded in 1951 by Bill Hendrix for overhead electrical distribution spacer insulators and cable applications. In the mid 1960's developed the polymer HPI (High Potential Insulator) Tie top insulators. They manufactured areial spacer cable systems, molded polymer insulators and insulater power cables. In 1970's they developed a vise top HPI insulator.. In 2012 they developed a line of polymer line post insulators. Hendrix insulators are used around the world and boast that their insulators are 100% recycable. Here is a picture of their secondary spool insulator marked Hendrix 53-2 A-Neck. Measures #3"X3" 7/8" hole.