Full Details

Name and Model Number System Tombeur, Advanced - Prototype
Country of Origin England
Date of Manufacture 2011
Front Scales , A [ CI, SI, , C ] D, AI,
Back Scales None
Scale Length 244 mm
Type of Rule Slide Rule
Construction Mahogany, Paper, Perspex
Area of Use Other
Comment Handmade forerunner of System Tombeur Advanced slide rules for jugglers.
Designed and made by Colin Tombeur.
Rarity RRRR
Donor Collection of Colin Tombeur
Match Number 74

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.