Full Details

Name and Model Number Selectron Model A
Country of Origin Switzerland
Date of Manufacture ~ 1960
Front Scales C/D
Back Scales None
Scale Length ~ 16 cm
Type of Rule Watch Type
Construction Metal
Area of Use Generic
Comment This Model A is very hard to find,
its all black face with white scales is
perhaps the more usual layout,
but makes for a very attractive and unusual
slide rule.
Rarity RRR
Donor Collection of Conrad Schure
Match Number 36

RR = Rare -- 1 of 25 collectors has one; it may take a year to find an example in the marketplace.   
RRR = Very rare -- only very few known to collectors; may take several years before one comes up for sale.   
RRRR = Extremely rare -- a museum piece; unlikely that an example will ever come up for sale.