Full Details

Name and Model Number	Jacob Zedak's Rav-Bo Computer
Country of Origin	Mandatorial Palestine
Date of Manufacture	~1942
Front Scales	C [D B K L Sin Tg Small-angle Sin+Tg]
Back Scales
Scale Length	43 cm
Type of Rule	Disc
Construction	Paper scales over plywood stator and rotor, celluloid cursor
Area of Use	Generic
Comment	See details at https://www.nzeldes.com/HOC/Zedak.htm
Rarity	RRR
Donor	Collection of Nathan Zeldes
Match Number	412
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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.