how to get value of $_

I have a test CSV file where the contents are as follows:

ID -> header

99999 -> value

the actual CSV will have more values.

I want to loop thru the CSV and get the value pointed to by $_ using this ( import-csv c:\siptest.csv | % { write-host $_ } ) but I get this:

@{ID=99999}

I tried $_.value but that didn't do anything.

how to get 99999 only?