I bought a base level PST, the sun was fun to look at but lacked the ability to show any surface detail. So it tended to sit more than get used. The SM40 comes packaged in a very nice foam lined hard case and a manual that covers several solar telescopes. The filter screws directly to the front of the PST and the adjustments are easy to learn from the well written instruction manual. With this second stack filter the suns ball really pops with surface detail in 3-D. Wow! If you have a Coronado PST single stack and want it to pop when viewing the sun, the SM40 works very well. I gave it four stars simply because I thought it costs too much. Aside from the cost being more than the whole PST, it's a value compared to buying another system.