X1C: Open SIM Card WW or Lenovo Mobile Access SIM?

[LondonConsultant]

I am about to order an X1 Carbon from Lenovo's UK online shop, but am unsure about the two options for Selectable SIM. I've searched online and couldn't find anything enhlightening. So, what's the difference between Open SIM Card WW and Lenovo Mobile Access SIM? Any explanation or recommendation appreciated... Thanks.

[TTY]

Here is some information from the U.S. website:
http://www.lenovo.com/products/us/lenovo-mobile-access/