Built-in power transformer (220V-50Hz). Quick or slow charging at choice. Compatible with Ni-MH/Ni-Cd rechargeable batteries. Can charge 1-4 pcs AA/AAA, C, D 6F66 battery. Specially suitable for batteries used by Reapter, Walkman, MP3 Player, Camera and Notebook, Electric Toys, etc. Output: AAA/AA Quick: 1.2V × 4 – 150-160mA; Slow: 1.2V × 4 – 90-100mA; C/D Quick: 1.2V × 4 – 200-220mA; Slow: 1.2V × 4 – 140-150mA; 6F22: 9V-16mA. Charging time numerical method: Charging time=1.3 ～1.5 * Battery Capacity(mAh)/Charging Current (mA), users have to control the charging time according the above numerical method to avoid overcharging and protect battery against damaging. With two flat pin plug.