At 4OVER4.COM, we offer clear and frosted business cards printing only 1-sided on 20-point plastic. These are printed CMYK. Since both of these materials are translucent, or semi-translucent, if you were to print on the backside, the art from the back would be viewable through the card and the card would become difficult to read. With that said, we can print double-sided clear and frosted business cards by printing CMYK + W where we add a white backer in the middle of your artwork to ensure that the art from the backside does not bleed through to the other side. This means you can design your card on both sides without any double exposure. Double-sided clear business cards are available for 30mil Frosted Plastic business cards https://www.4over4.com/printing/30mil-frosted-plastic-cards