| Name | Keuffel & Esser 4090 Original prototype for 4090 Universal rule Variant |
| Front Scales | A = B C = D DF = C S = A |
| Back Scales | A = BI CI = D DF = CI L T = D |
| Type of Rule | slide rule |
| Material | engine divided celluloid laminated mahogany |
| Dimension (mm) | |
| Area of Use | generic |
| Origin of Rule | Bob Otnes |
| Match Number | 4622 |
| Comment | |
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