|Name and Model Number
|DEVCO Pencil Slide Rule
Sylvania No 400F
|Country of Origin
|Date of Manufacture
|IN A DF CF CI C D L K
|10 cm (4 inches)
|Type of Rule
|Plastic with painted scales, pencils on each end
|Area of Use
|This novelty slide rule has a double ended pencil.
|Collection of Clay Castleberry
(Click Picture for Details)
|In conjunction with our 'donors' we assign a rarity rating to each item, based on the system devised by Herman van Herwijnen
|(1929 - 2004), renowned Dutch collector, author, and creator of Herman's Archive, a collection of 5,000 slide rule images on CD.
|• RR = Rare - 1 of 25 collectors has one; it may take a year to find an example in the marketplace.
|• RRR = Very Rare - only a few known to collectors; may be several years before it comes up for sale.
|• RRRR = Extremely Rare - a museum piece; unlikely that an example will come up for sale.