When I replaced mine on my H30, I went with the original Greys because of the sizes. I needed two different sizes and didn't want to mess with filling in a couple of holes in the cabin. I could only get the NFM ones in the smaller size I needed. Others were so expensive that that wasn't an option. I believe I bought them through this site but can't remember that far back. I do know that it's been more than 10 years and no leaks yet.