I have a few cut open filters that the louvers looked almost closed in sections, but when viewed from the other side they were well opened.
Not many talk about the rough edges on the louver holes, it could be steel is broken loose, on it's way to the main bearings. Have yet to see smoothly made louvers.
Not many talk about the rough edges on the louver holes, it could be steel is broken loose, on it's way to the main bearings. Have yet to see smoothly made louvers.