What paper are PostBug postcards or letters printed on?

• The paper for both postcards and letters is from 100% recycled paper stock, and is 100% recyclable in normal paper recycling systems.
• Postcards have a high quality look and feel (letters too, but it is normal printer paper)
• Postcards are full colour glossy format on thick 'card stock' paper.
• Letters are up to two sides of text and then folded into a stamped envelope.