We ordered a couple of the MERV 13 in a custom size for our 30-some year old furnace that wouldn't take regular store-bought sizes. The custom filters arrived very quickly and are good quality. We put the first one in, fits like a glove, and we feel a lot more comfortable having a filter that fits well. Will be re-ordering.
These filters seem great, although I was planning to take them apart to make face masks. Very difficult to take apart because of the cardboard lattice, and the metal lattice under that. Solid filter, with great buyability. (Anywhere else wanted to sell me a pack of at least 6, but I only wanted 2.)
I really think the slide on to my heater is to tight. Your filter made it easier than the flimsy products but I think I still need a more solid material for the outside of the filter.