yoga brick: use cork as material,free of formaldehyde meet customized size is viable, stetch body enogh and prevent injury. yoga brick 1) also called yoga block,use cork as material,free of formaldehyde.2) size is 20*15.5*9.5cm, customized size can be discussed.3) stetch body enogh and prevent injury.4) different colorful design and logo printing is available as well.. raw material: