E. F. Johnson Company Product. Stand-Off Insulator. Material: ceramic, metal. Size: 2 1/2" W. x 4 1/2" L. Description: white porcelain - upright cone shaped Type 135-60 stand-off insulator - threaded screw end and nut on one end - square base on other end - horizontal ridges from one end to the other. See reference in comment section. Product on display board.