DescriptionLayered, prototype drawings of a Mallory Duracell Lithium Battery, LS 501, 1.8/15 Volts. There is a handwritten note in cursive on the top, translucent layer of paper that says "OKed by DD 8/9/72 10:20 AM". There is a blue sticker on the bottom, right-hand corner of a Mallory Organic Lithium Battery wrap, LO-28, 3 Volts. Both the illustration board layer and the top, paper layer have scaled measurements on it. Typed onto the back of the illustration board in black ink is "139U07". Made on green-backed, Crescent Illustration Board, Hot Press Surface, No. 200, Heavy Weight.