VBA for looping VLookup to last row with data

In the attached workbook in column B (sheet "Upgrade Info") is a list of serial numbers in this format 326ABS3472. On the sheet "APC" is a range of APC Codes and corresponding short descriptions. The APC code is made up of the first three characters of the serial numbers in column B (sheet "Upgrade Info").

What I am trying to do is look at the first three characters in column B (sheet "Upgrade Info"), match that with the short description on the APC sheet, and return the value to column E of the Upgrade Info sheet. I will not know how many rows the sheet will have so it needs to loop to the last row containing data. The first row containing data will always be row 15.