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 table_25572068_1 ( date VARCHAR, series VARCHAR )

### Question ###
When was the F4 7 series?

### Accurate SQL ###

SELECT date FROM table_25572068_1 WHERE series = "F4 7"