Unit power control only starts working when pot meter is opened for 80%. Control range is between 80% and 100% instead of 0% to 100%. But the unit operates fine.
it is just a pity not to have the voltage regulator as it has in the image of the purchase, but only a light in place of the display and pity that the seller does not specify that there is no voltage display, but a light to inform that the device is on . I just made the purchase because I thought it had a display as in the picture but it was my mistake for not confirming the specifications.