If you mean the item hex code for creating an item quickslot, try looking at:
https://spreadsheets.google.com/ccc?...thkey=CP-x8KUJ
Of course, there are quite a few heavy shields, even at level 20, so you'd have to know the name of the shield you are trying to find.
If you can give a bit more information about what you are looking for we can probably give a better answer.