Isolation between primary and secondary looks good (separate windings). Markings on the item itself are in Chinese, not English as depicted, so I had to look up in the original listing, which side is the primary (red wires on mine). Loading this transformer with a ~ 100 Ohms (current draw of 83 mA) makes the voltage drop to less than 9 VAC, but enough to have it regulated to 9 VDC by any linear regulator.
the description is in chinese, this for sending to europe. i would like to know what wires should be connected to 220V: red or black ?