[0.1 lb] I have been trying to figure out a way to protect my Sony mirrorless camera sensor from dust and particles.  

My biggest concern with mirrorless cameras is how quickly the camera sensor can get dirty.  

These KASE filters have solved that problem. 

By using a UV or ND filter that fits directly, and safely, in front of the sensor.  These filters protect the camera sensor from outside exposure when switching lenses.  This comes with a carrying case that can hold two additional filters, 3 ND filters, 1 UV filter, cleaning cloth, a guitar pick to remove the filter, finger rubber gloves, & instructions.

Pros:
1. No need to add an ND filter for different sizes of lenses
2. Protects the camera sensor from dust and moisture
3. Comes with 3 different ND filters for your specific scenario
4. Includes a soft frame pad that sits nicely below the filter for prolonged use
5. Very easy to remove or install
6. No overheating issues or problems when using the entire day
7. Excellent video and image quality

Cons:
It doesn't have a snug fit in the Sony a7sIII.  If you remove your lens and your camera body is tilting forward, it can easily fall out.  The instructional video shows that these filters clip-in.  However, I believe the dimensions are slightly larger for the a7sIII.  So to be safe, you will want to remove your camera lenses with the body facing up.  

All in all, this is an excellent innovative product!

[0.1 lb] This filter fits the A7R IV perfect. Be sure to place it in with the letters towards the camera and press the top until you feel the click. I have had no issues with it. It does a good job reducing the yellow in night photography and making the colors of light more realistic. Hard to beat for the price and convenience of using it with any lens.

[Dedicated] My friend has these and told me to get them. So I did no questions asked. I can't wait to point my camera directly at the sun and not be blinded. I think that's all I can ask

[3.7 x 3 x 0.7"] As described.

[0.1 lb] I have tested this on the a7iii and now a7iv, it works great!
My main concern with an nd filter at this price point was a noticeable color shift in the image as I have experienced with other ND filters. There is no color change with the ND Filter in. The clip in filter works well even without the supplied pads to cover any open spaces.
The other obvious advantage of this filter is that it works with all of my lenses, and I don't have to carry around step down or step up filter rings.

[0.1 lb] I love the fact that this stays in the camera and does not have to be changed with the lens. Saves lots of $, and helps with image quality. And the quality looks really great. I'm not noticing any color issues. I'm also not having any looseness issues. It's nicely snug, but easily removable. I was concerned after reading another review, but this copy was able to remain in place with the camera pointed straight down during lens changes. The ND 8 is the lightest filtering, but it seems like plenty for most situations. I'll be ordering more for my other cameras, but most likely all ND8 because unless I were in extremely bright light this seems like the sweet spot for me.

[0.1 lb] I have never used an ND filter before. Novice review: Every youtube vid I've seen on ND filters talk abut color shift or color cast. I don't see it here!
I'm thrilled to use 1 ND filter for all of my different lenses.
Examples probably do not truly highlight the benefit of ND filters but it was my first forray.

[Dedicated] This very well made filter helps create more dramatic IR black and white images with more contrast.

[3.7 x 3 x 0.7"] Shooting with the A7S3 @12800 ISO almost performs like a converted body for BW photography. I get nice results without slow shutter. Also love that I can use this filter with any lens. It really shines with the Sigma 14 1.8. Great entry point for IR if you have the a7S3. Check the customer images to see a few shot results.

[Dedicated] Glass seems to be high quality. Works as expected.