c. 1920's original american industrial "new old stock" galvanized pressed and formed steel single incandescent lamp or light bulb cage or guard designed (and likely patented) by the mcgill mfg. co., valparasio, ind. the "loxon" bulb guard was designed to prevent damage and even theft of the light bulb with the use of a specially made key to "unlock" the cage enclosing the bulb. the diminutive bulb guard remains in great overall condition, considering age. regular set screws can be used to replace the original screws requiring the key. measures approximately 3 1/4 inches in diameter with a height of 4 inches.