| Name | Keuffel & Esser 1744 Duplex with arithmetical slide, dated 1895, Cox's Patent |
| Front Scales | A = B C = D |
| Back Scales | A = BI CI = D |
| Type of Rule | slide rule |
| Material | engine divided celluloid laminated wood |
| Dimension (mm) | |
| Area of Use | generic |
| Origin of Rule | Michael O'Leary |
| Match Number | 4020 |
| Comment | |
| Thumbnail |  |