'Frog' Matsumoto Hoji ©The British Museum Sustainable WOODEN gifts to send and to keep. Postcard back. Send anywhere in the world. Each card measures 15cm/5.9" by 10cm/3.9" and is 4mm/0.2" thick. - Sustainable WOODEN MAGNETS. Magnetic back. Each magnet measures 10cm/3.9" by 7.5cm/6" and is 4mm/0.2" thick. Eco-friendly packaging, magnets are simply banded and boxed for transport. Sustainable wood printed in England. Made by The Wooden Postcard Co - a carbon-neutral business who plant trees with Ecologi.