The fit was a little tight and had to push hard to get it in, I measured it against the original filter that came with the unit, and it didn't seem to be any difference in size. The original filter had metal frame so I wonder if that meant a closer tolerance, the Filterbuy filter is cardboard framed which by it's nature has a higher friction coefficient.
The filters fit and work well. But they are pricey. The filter size needed was not common. It is normal stock for Filterbuy so I purchased it there. However, the price is very high compared to similar filters, albeit not the exact size.