Vintage Western Electric 3A photoelectric cell-tennis ball phototube, Made In USA, overall height 4.25 in, diameter 2.25 in, circa 1950s. Photo by Joe Haupt, uploaded on Flickr under a free CC-BY-SA-2.0 license.

Flicrk file: www.flickr.com/photos/51764518@N02/28449299529

Short URL: flic.kr/p/KkY6Ai