Regarding operational verification, the playback and volume adjustment functions when connected to a CD player and speakers are working correctly. Other functions have not been confirmed, so this item is being sold as-is. The following content was automatically generated, please refer to it: 3/5 channel BTL connection power amplifier, with center volume and rear volume adjustment functions. - Model Name: AVA-505 - Number of Channels: 3/5 channels - Connection Type: BTL connection - Volume Adjustment Functions: Center volume adjustment, rear volume adjustment Thank you for viewing.