The Soshine AA to D-size cell battery converter case is used to convert the AA to D-size cell battery. Just stick the AA battery in the converter and it's the same as a D-size cell battery. The battery converter case is perfect for electronics and emergency situations. The case is a good gadget to keep close at hand、 at home、 at the office、 etc.<br /><br /><li>Put an AA battery into the battery converter </li><li>Check the polarity setting. The polarity signs (+/-) are marked on the battery converter </li><li>The battery converter can be used as a D-size battery </li><br /> The Soshine AA to D-size cell battery converter case is used to convert the AA to D-size cell battery. Just stick the AA battery in the converter and it's the same as a D-size cell battery. The battery converter case is perfect for electronics and emergency situations. The case is a good gadget to keep close at hand、 at home、 at the office、 etc.<br /><br /><li>Put an AA battery into the battery converter </li><li>Check the polarity setting. The polarity signs (+/-) are marked on the battery converter </li><li>The battery converter can be used as a D-size battery </li>                                                                                                                                Dimensions: 2.36 in x 1.3 in x 1.38 in<br />Weight: 0.46 oz