The reason for the defect is that the cover on one side of the moving part is broken, as shown in image 3. There is no problem with the operation, but please refrain from purchasing if you are concerned. Used less than 10 times. Due to the nature of the product, there may be some scratches and light dirt other than the broken cover, but there are no noticeable scratches or stains. There are no instructions or mat. Please search online for how to use it. We only ask that those who understand the above and that this is a used item purchase.