| Name and Model Number | Cooper |
| Country of Origin | England |
| Date of Manufacture | ~1930 |
| Front Scales | C |
| Back Scales | |
| Scale Length | 100" |
| Type of Rule | Slide Rule |
| Construction | Wood |
| Area of Use | Generic |
| Comment | Grid-iron type rule with 20 scales each 5" long. |
| Rarity | RRR |
| Donor | Collection of Rod Lovett |
| Match Number | 91 |
| Thumbnail |  |
| RR | = Rare -- 1 of 25 collectors has one; it may take a year to find an example in the marketplace. |
| RRR | = Very rare -- only very few known to collectors; may take several years before one comes up for sale. |
| RRRR | = Extremely rare -- a museum piece; unlikely that an example will ever come up for sale. |