There isn't much to say really about the T Rex DC Polarity Invers. They do exactly what they are meant to with no fuss. I play quite loud at gigs and I am obsessed with retaining as much sonic clarity as is possible and Even I cannot notice a "hum" or "fizz" or anything of the like from this product. Worked well for me and saved me having to buy a new power supply. Very handy to have,as long as you have researched thoroughly the polarity and current of your pedal!A friend of mine who plays bass,tried using a product like this,to provide power for one of his pedals without examining the polarity of the pedal and managed to fry the circuit board so i would plead with anyone considering buying one of these to just do a few minutes research and save yourself the heartbreak of destroying your pedal!My only complaint about the product is the length of it. I would have preferred a slightly longer lead,purely for the purpose of ease,yet in saying this I would not like my sound to diminished for this to be the case. Overall I was very happy with this purchase. What can I say really other than good price and works perfectly!