Bergeon Eye Loupe 2611 for watch makers has an aluminum ring that can be removed to change the lens, available in 4 powers:
| Distance (in inches) | Magnification |
| 1.5 | 7 |
| 2 | 5 |
| 2.5 | 4 |
| 3 | 3 |
Take the first row for example,Loupe size 1.5 this means that at 1.5 inches away from the object, the loup will magnify the object to7x its normal size.
Make sure to select the distance x magnification that suits you.