I don't include product information on the back of our card. We print a seperate slip to include in the box with pen type, material and where the material came from. Also included is basic care, refill info as well as our contact info. These are printed up ahead of time and I simply fill out material type and slip it in the box, along with our business card. The box also has a small sticker inside the lid. As I'm writing up the sale ,If I haven't already I'll tell them about the material and related any interesting stories about the material or pen. By the time I've completed a sale the customer has at least three contact references, sometimes four if they have also picked up one of my cards plus info about the pen on a somewhat personal level. This has paid off numerous times with repeat customers and call backs.