I bought this pedal to use it as a volume pedal but, for this price, this is a must buy for DIY enthusiasts. Out of the box, it works well, but the plastic box dos not provide shielding, so, it is sensible to RF interference. I solved it covering the inside with Aluminium duct tape connected to ground, and it worked perfectly.
This pedal may be modded to use as expression pedal, or even Wha Wha enclosure box. Although it is made of plastic, it is rough enough. The stock pot is a standard 16mm body diameter, knurled 6mm shaft with 100K, which is not the best for extreme use, bot it is very cheap to replace or inprove.