Installed first one yesterday. The filter was about an 1/8 of an inch too big, but a little persuasion I got it in.The filters are quality made and very reasonable prices.Would highly recommend. Super fast delivery as well.
On the filters, I checked the cfm the 18 plrat wasProx 1100 cfm while your 18 pleat is less than 900 cfm. found one filter rated 1300 while your was rated at 11 merv and yours had lower fm than the 13 merv. .
The filters look fine but not crazy about the way the filter rows are out of alignment where some rows are glued together with no space to filter through.