Full Details

Name and Model Number DEVCO Pencil Slide Rule
Sylvania No 400F
Country of Origin USA
Date of Manufacture Estimate 1950-60s
Front Scales IN A DF CF CI C D L K
Back Scales None
Scale Length 10 cm (4 inches)
Type of Rule Slide Rule
Construction Plastic with painted scales, pencils on each end
Area of Use Generic
Comment This novelty slide rule has a double ended pencil.
Rarity RRR
Donor Collection of Clay Castleberry
Match Number 318
(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.