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_name_50 ( class VARCHAR, erp_w VARCHAR, call_sign VARCHAR )

### Question ###
What is the Class for the ERP W of more than 2 and the call sign of w223au?

### Accurate SQL ###

SELECT class FROM table_name_50 WHERE erp_w > 2 AND call_sign = "w223au"