| Name | Keuffel & Esser < 4071 > Duplex |
| Front Scales | A = B C = D |
| Back Scales | A = BI CI = D |
| Type of Rule | slide rule |
| Material | Engine divided celluloid laminated mahogany |
| Dimension (mm) | 308x27x6.7 |
| Area of Use | generic |
| Origin of Rule | Michael O'Leary |
| Match Number | 4189 |
| Comment | |
| Thumbnail |  |