| Name | Keuffel & Esser 4071 T Duplex, with Trig Scales, dated 1915 |
| Front Scales | A = B S C = D |
| Back Scales | A = BI T CI = D ] L |
| Type of Rule | |
| Material | Engine divided celluloid laminated mahogany |
| Dimension (mm) | |
| Area of Use | |
| Origin of Rule | Michael O'Leary |
| Match Number | 4197 |
| Comment | |
| Thumbnail | No Picture |