No issues confirmed with operation. A classic BOSS guitar effects pedal set of three: Overdrive → Phaser → Delay. I think this is a fundamental set, and in the extreme, these three pedals are sufficient. I've used them for many years, so as you can see, there are scratches and dirt. Regarding the DD-3, it's from when it was first released, and I believe it's from the initial production run, which is now discontinued. ※ Please check the images carefully for scratches and dirt. Also, in images 7-11, I took pictures to show the scratches on the DD-3, which has the most wear and tear, as much as possible. I hope this helps you. - Model: Super OverDrive SD-1 - Model: Phase Shifter PH-3 - Model: Digital Delay DD-3 - Power: 9V battery, DC9V adapter How about this set for beginners or as an opportunity to return to the basics? Please consider purchasing.