The Hershel Solar Wedge is a right-angle viewing attachment for solar observation. It reduces the intensity of the sun for safe viewing with larger apertures.
The Herschel wedge is a fantastic way of observing the sun in white light.
You need to take some precautions. There is still enough light passing true to harm your eyes.
First you need to open the metal cover at the back of the wedge. Be careful the back of the wedge can be very warm.
At the eyepiece side you must use a Neutral Density filter of factor 5. Best is to use a screw in filter.
If it is the first time you use the wedge put the solar diaphragm in front of the lens.
Is the solar image to dim remove the diaphragm.
I use the Polarex Herschel Wedge all the time in combination with my 10cm Polarex and it’s great.