c. 1915-20 original and unrestored american industrial electric incandescent lamp metallic cage or bulb guard, designed and patented by otto johnson of la grange, il. the industrial "flexco-lok" cage or guard is secured to the lamp socket so as to enclose the light bulb and protect it from injury. the two guard sections are hinged together at their lower ends and adapted to be releasably connected together at their upper ends so as to enclose the shell of the socket between them. the cage is comprised of a plurality of bent and twisted steel "ribs" conforming to the curvature of the light bulb on one end and a pressed and formed sheet metal reflector on the opposite end. the portable steel lamp guard was fabricated by the flexible steel lacing co. (flexco), chicago, il. the original green enameled finish remains partially intact. the twisted steel wire hook pivots back and forth. measures approximately 4 x 4 x 6 inches.