The pen is round, and if you want to print a circle, you need a screen printing machine or a heat transfer printing machine. It only prints on one side of the circle, which can be pad printed. The cost depends on the number of colors printed and the quantity. It’s up to you to decide. Both screen printing and pad printing require color registration, which is more troublesome and suitable for small quantities of printing. The heat transfer mold will be more expensive, and a heat transfer film will be required, but the quality is the best, and the higher the quantity, the higher the price. The cost will also be reduced.