I cracked one open out of curiosity. A solder ball fell out, about 1/8″ size, big enough to cause trouble and it shouldn’t have been there. Other than that I didn’t see any quality problems. But now I see why this type of product design can easily injure people; there’s very little isolation and it’s not hermetically sealed. So use in a damp environment or submersion even briefly can cause a short circuit that results in a dangerous condition, especially if used at 220VAC.