| Name | Davis & Son Variant |
| Front Scales | 25cm / A = B C = D ] 10inch #11-20inch# |
| Back Scales | = S L T = |
| Type of Rule | slide rule |
| Material | wood/plastic |
| Dimension (mm) | 259x31.8x10 |
| Area of Use | generic |
| Origin of Rule | Herman van Herwijnen |
| Match Number | 688 |
| Comment | |
| Thumbnail |  |