| Manufacturer | Gruen |
| Caliber Reference | Gruen 115 |
| Movement Type | Manual |
| Diameter (Lignes) | — |
| Diameter (mm) | 21.99 mm |
| Height / Thickness | 3.5 mm |
| Jewel Count | 15 Jewels |
| Beat Rate / Frequency | 18,000 BPH |
| Lift Angle | 51° |
| Power Reserve | 38 hours |
| Escapement | Swiss Lever |
| Production Period | 1925 |
The Gruen 115 is a celebrated example of vintage precision engineering. Featuring 15 jewels and operating at 18,000 BPH, surviving examples are prized by collectors and restorers.