Three times we ordered 14 pieces conveniently and two pieces were initial malfunction. I think that it can not be helped a certain number of defective products appear due to the quite delicate nature of this product. (Because the shipping company handled it somewhat roughly or it was out, but it is troublesome for the replacement afterwards. The procedure guide is also incomplete so it can not flow properly, I think that it takes too much time and time until good items arrive. Although it seems that the flow is made if it is a case of returning for the convenience of the purchaser side, it is thankful because the price is cheap, but if there is not enough time, it is ok to the extent that the defective item will come out You may as well order better.