This is a compact and easy-to-use bass effects unit with 24 effects and an auto-tuner. - Model Name: ZOOM 506 BASS - Number of Effects: 24 effects - Number of Programs: 24 programs - Tuner Function: Auto-chromatic tuner - Simulator: Amp simulator Thank you for looking. I tested it with a 9V battery and it works without any problems. As you can see in the pictures, there are some scratches, but overall it's in good condition. Please understand that this is a used item before purchasing.