In this combined picture are the 3" and 7 1/4" porcelain standoffs embossed Sensory and a radio lightning arrester marked 20th Century sold by Armstrong & White Co. Chesiwick, PA.. I have put it beside the Sensory arrester so as you can see they used the same type mold. Who made the porcelain pieces is another mystery and if Armstrong & White Co. was somehow related to Heinemann Electric Co. Philidelphia, PA. & Trenton, N.J. is another question too. Also in he picture are three arrester boxes from A&W and Heiemann for the 20th Century, Sensory, and Gaurdaset pieces. The arresters and strains are hard enough to find but when they are with the original boxes, (which were usually thrown away), can be a wealth of information. Not to mention a lot of them had neat graphics too.