| Rotation speed measurement | |
| Range | Optical (non-contact) measurement: 1 to 99999 revolutions/minute Contact measurement: 1 to 19999 revolutions/minute (Fluke 931 only) |
| Precision | ±0.02%RD+1 |
| Sensing distance | (optical) 500 mm |
| Specifications | |
| Battery type | (2) 1.5V LR6 (alkaline) AA battery |
| Battery life | About 40 hours |
| Operating temperature | 0°C to 50°C |
| Storage temperature | -20°C to 70°C |
| Weight | 250 g |
| Dimensions | 175 × 60 × 28 mm |
| Warranty period | 1 year |