Credit rating made of chip-board/particle board/press-board (small chips of wood held along with glue) in addition they are wet for over a few hours they absorb water, expand, and lose their structural integrity. https://7fx2fkj2aumum3glr2kk66ghdvq3kmf4rz23gsnrydclv5gpcoga.Cdn.ampproject.org/c/Mongdol.net%2Fbbs%2Fboard.php%3Fbo_table%3Dfree%26wr_id%3D2825870