Solar Filter 60mm Black Polymer

Seems to work well so far

I'd give 4.5 stars if I could. The instructions for getting the right fit were a little confusing--my binoculars are ~51mm in outer diameter, so I decided to buy the 60mm solar filter since 50mm apparently would have been too small. The problem with the 60mm filter is that one layer of felt tape isn't enough for a tight fit--I had to cut 3 pieces, apply them to the inside of the filter, then cut 3 more and apply them on top of the other ones. I'm not sure if the 50mm would have worked or not, so I am just going to keep these. I am sure I can find some third-party felt tape that's thicker if I really want to. As far as solar viewing goes, they seem to work as advertised! I can see sunspots even though my binoculars are only 8x power. I can imagine with a telescope these filters would work great. My only two complaints are that getting the fitting right can be tricky depending on your device, and the durability of the filter is a little questionable but you get what you pay for. Hopefully they will last a little while but time will tell.