| Name | Keuffel & Esser N < 4102 > Surveyor's Duplex |
| Front Scales | Vert. 1/2 Sin 2a A = B Ci C = D Vert. 1/2 Sin 2a |
| Back Scales | D Sin d = Cos l&h C Tan = Tan I Az |
| Type of Rule | slide rule |
| Material | Engine divided celluloid laminated mahogany |
| Dimension (mm) | |
| Area of Use | generic |
| Origin of Rule | Michael O'Leary |
| Match Number | 4403 |
| Comment | |
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