I have no idea how these were used or what for except radio but would love to see a picture of one in use or advertisement. These are hard to find Ohm resistors that I was told were used for radios and screwed into a lamp socket. They are very neat looking and made of porcelain with glazed over wire. Left to right. Dark Brown glaze Chocolate cap 3.5 ohm 11 inches long, Next is Black glaze marked HEB7300/WL 7914 5.5 inches long, This next NN one has an outside adjustable resistor in green glaze and is 5.5 inches long. The next one is in a beautiful dark cobalt blue glaze marked 100R Bryant 400. and is 5.5 inches long. I've looked in the Bryant catalogs I have plus online and can't find any info on it. Last is a Chocolate brown glaze marked 5 and is 11 inches long. If you have a picture of these in use or can tell me how they were used I'd love to hear from you. Neat stuff.