Update Query, updating wrong table

What am I doing wrong? Here is the SQL of the update query:
UPDATE tblTestUpdate INNER JOIN tblImportProducts ON
tblTestUpdate.MaterialNumber = tblImportProducts.MaterialNumber SET
tblImportProducts.Each = [tblTestUpdate].[Each]
WHERE (((tblImportProducts.Each)<>IsNull([tblImportProducts].
[Each])));

It keeps updating the wrong table (tblImportProducts)... it will take
the value's which match from tblTestUpdate and put it in the
corresponding fields on tblImportProducts. I am trying to do the exact
opposite

Thanks,
Matt Pierringer

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