Topdrawer 100% Cotton 4x6 Watercolor Postcards are made from premium 140lb cold press, professional grade, French watercolor paper. The heavyweight cotton paper has superior surface strength and is ideal for watercolor, gouache, acrylic, marker, pen, pencil, and much more. It can withstand multiple washes and your colors stay rich and vibrant. Topdrawer Watercolor Postcards are blank on one side, and letterpressed on the other by a master printer in the USA. They are are very easy to use. Simply create your masterpiece, fill out the destination, place a stamp, and drop it in the mail. Each pack contains 15 watercolor postcards measuring 4” x 6” (10cm x 15cm).