This is a high-precision tuner made by Steinberger, featuring a stretch tuner function (also has modes for tuning guitars, etc.) and various pitch settings. I purchased this new, as it was being sold during a warehouse clearance. The box has some scratches, but the tuner works and all accessories are included. Please understand that this is from that time period. Power source is 9V or battery (the original one is included). The accuracy is, I believe, equivalent to a PolyTune 2. It has input and output jacks. - Model Name: Stretch Chromatina 501 - Brand Name: Steinberger - Function: Stretch Tuner - Type: Tuner