Telrad makes the simplest and most comfortable sighting tools in the astronomy industry. It features a large, dimmable reticle that can be that you can easily see with both eyes open. The Telrad can fit on to any telescope using the double adhesive foam padding.  Etra mounting bases are also available for this finderscope so that you can use the same finder on all of your telescopes. It's no wonder that many astronomers have swapped out their finders for a Telrad.