This is a Sky Blue Overdrive from the Mad Professor HW era. It's very rare to find these used. I purchased it new directly and have stored it in its case, taking it out periodically for use. During the most recent check, I couldn't detect any scratchiness in the switches or pots. There were also no operational issues. It's an OD that's said to allow for a variety of tones by combining the Z and texture knobs, but honestly, I really like it because you can get a juicy tone that's perfect for both distorted backing and leads without having to think too hard about it. Like my other listings, I'm reluctantly putting it up for sale. While no issues were found during the most recent check, please understand that due to the nature of used items, sales are final and returns are not accepted. - Model Name: Sky Blue Overdrive - Brand: MAD PROFESSOR - Condition: Handwired - Accessories: Instruction manual, box Thank you for looking.