User Summary: Raging River Terrain Tray - Multi-pack is part of the Wildlands wilderness terrain series. Terrain trays are made of thin ferrous metal sheet so the magnetic pieces can stick to it. Different terrain artwork printed on the surface of each side. They come in gridded and gridless versions. This This item was initially available as an add-on during the Wildlands Kickstarter. Raging River Terrain Tray - Multi-pack comes with these 6 pieces. (2) Raging River Straight / Mountain Lake 12x12 (2) Raging River Curve / River Mouth 12x12 (2) Raging River Straight / River Curve 6x6