Semi-absorbent panels with gesso coating on strong MDF board. Can be used for acrylic, watercolor, oil, tempera. The outer frame is made of highly strong perch wood that is less warping. Available in 22mm and 41mm thicknesses. Available in 14 sizes from F0 to F10, S0 to S10. Made of beautiful wood grain birch wood, so you can use the artwork as it is without framing. Not only is it a drawing material, but it is also great for collages and other substrates that require strength.

(From Amazon.co.jp)