With this accessory you can safely observe the Sun by projecting the sun on the white box at the bottom of the pyramid. To see the sun in the so-called white light and can study in peace and relaxed insight sunspots - a transit of Mercury is so observable.
By projecting you will get a big sun image that is thanks to the lateral shielding from sunlight contrasting rich.
Another advantage of the projection method is that several people can observe simultaneously, for example, school classes.
The pyramid can be easily attached like a 1.25 "eyepiece. Your telescope should have a diagonal mirror or Amici prism. Ideal is the use of the pyramid at Refractors (lens telescopes).
You should only use inexpensive eyepieces. The heating may in expensive eyepieces result with many optical elements in damage to the compounds of these elements. You should also choose the focal length of the eyepiece large enough so that the sun fits clearly into view. This makes the entire sunlight passes through the eyepiece.