The KORG Pitchblack Advance is a high-precision digital tuner with a compact black design. Operation confirmed. Immediate purchase is welcome. This is a used item, so please understand that it is non-refundable and non-returnable. - Brand: KORG - Model Name: Pitchblack Advance - Power Supply: 9V battery or AC adapter - Included Accessories: Box - Display Type: Digital - Color: Black From the manufacturer's website: "Ultra-high precision tuning that can be adjusted to ±0.1 cent. 4 types of meter display modes. True bypass that does not affect the sound at all. DC out for parallel connection. Complete avoidance of noise when using a power supply."