This post is for informational purposes only. Please review the manufacturer documentation before using any part as a replacement.
UA01-4 is a filter for HVAC applications that we stopped carrying some time ago, I believe it is still out there, but if you need an easy alternate, part number 19-EA01-4-ND, which is from the same product line, should be suitable for most cases.
It is essentially a higher MPR version of the same filter, both have a MERV 13 rating and dimensions of 16"x25"x1". The UA01-4 is 1900MPR while the 19-EA01-4-ND is 2200MPR. That was the only significant difference I could find, but as always I encourage you to look over the manufacturer’s available information to verify.