I saw real samples of business cards to be probably at least 400 gsm. However, laser printers go only upto 350 gsm (like some Xerox machines), unless they are from Intec or Xante, whos reliability and print quality I question. The material might not even be paper, and might be (light) board...
I know this forum is about printers, but does anyone know brands/models of flash stamp machines? There are many on ebay and alibaba, but it is better to buy from an established brand. Thanks