2 "neutral density filter with optical density 3.0 Transmission 0.1%-damping factor 1000 x. When looking at the sun, only use as an additional filter!
The fineoptical polish of our filters means that even with a Filter position of 20 inch or 11.81 (30 cm) before the focal point there is no loss of sharpness with large magnifications.
If you need to reduce overexposure and a Filter far before the focal point to be used (e.g. Before binoculars), the neutral Filter is just right.