| Name | Keuffel & Esser < 4138 > Morrison Radio Engineer's Slide Rule |
| Front Scales | (F left) L F A = B CI C = D T ST S (F Rt) db FREQ L C = = |
| Back Scales | (Left) 9 8 = 7 6 5 4 = 3 2 1 (Right) Att. Factor II Att. Factor I = d,Miles Cd P,Watts f,Mc = (sigma),emu E,microwatt/m db |
| Type of Rule | slide rule |
| Material | Engine divided celluloid laminated mahogany |
| Dimension (mm) | |
| Area of Use | log/tech |
| Origin of Rule | Michael O'Leary |
| Match Number | 4427 |
| Comment | |
| Thumbnail |  |