The black and silver and white and silver sample photos look like they may be using HASL surface finish (aka, solder).

If you're handing out business cards with a HASL finish, make sure to spend extra for the lead-free version.

The site gives you a .zip to download with your design

Inside the .zip is a README.txt and Elecrow.png

If the user selected "silver" the readme and image shows to select HASL lead free

:)