Features: 10in1 design,more useful,Use this product to reple the LR6 AA LR03 AAA battery,which is pre-configured with Black current-limiting power pks,and yellow is straight through. 1x Black Dummy Fake battery output is 4.5V Reple 3x AA or AAA battery,2x Black Dummy Fake battery Reple 2x AA or AAA battery,Yellow Dummy Fake Battery is Link function. This eliminates the need for 2x or 3x 1.5V AA AAA batteries,Never change batteries again! This battery replement allows you to use prtically any device that is only powered by 3 AAA or AA batteries. Suitable for Radio,electric toy,Christmas holiday LED lights,luminara candles,Interphone,Walkie talkie,Calculator,power remote controller,keyboard,Christmas advent calendar display,and more 3V or 4.5V power supply devices No Need To Change Battery Frequently: With this AA AAA battery adapter,you don'for t need to buy a lot of replement batteries when the batteries run out,saving you more for time and money.