1.Minimum value of punching pliers: 0.2mm (3 pieces of A4 paper), maximum value: 7mm; Optimal punching thickness: 0.2-4.5mm; If the thickness of the punch hole is greater than 4.5mm, more effort is needed to make the hole. 2.If you cannot drill holes in the belt, place a board of 0.2-0.25mm thickness under the belt. This board does not need to be specially purchased. All you have to do is take a small piece out of a discarded express box. 3.Arrange the size of the holes from large to small in the direction of the arrow so that you can quickly select the size you need. Note: opening a hole on the belt can only rotate in one direction, not in both directions (rotation direction is indicated by arrows).