The 19in by 19in filter was actually 20 7/8 by 20 7/8. A sticker on the frame said 19 by 19, but the fine print on the end cap says actual size is 20 7/8 by 20 7/8. So totally useless to me unless I cut it down to fit. A second filter I bought was the correct size that is was advertised as.
I have been using the filters for about three weeks and so far, I am giving them five stars. The dust seems to be much better. I prolonged the replacement of my filters because I did not have any. My measurements are very hard to find in a regular store.
I ordered a custom filter and it was accurate to about 1/16" on all dimensions! That's great! I ordered a MERV 8 but I think I will go with the next grade up next time. I just have to make sure my heater can handle it.