Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE resultsdata15 ( sample_pk number, commod text, commtype text, lab text, pestcode text, testclass text, concen number, lod number, conunit text, confmethod text, confmethod2 text, annotate text, quantitate text, mean text, extract text, determin text )
TABLE: CREATE TABLE sampledata15 ( sample_pk number, state text, year text, month text, day text, site text, commod text, source_id text, variety text, origin text, country text, disttype text, commtype text, claim text, quantity number, growst text, packst text, distst text )

### Question ###
What's the unit of measure used for the product commodity code PO?

### Accurate SQL ###

SELECT conunit FROM resultsdata15 WHERE commod = "PO"