... , clear display, easy to write and erase, no reflection, no distortion. The board is seamless spliced, eyesight protective. Surface roughness: ... 12μm Glossiness: 6%, no obvious glare. Ash tray: installed under board frame, removable for cleaning. Pulley: 4 ... quality paperboard, thickness10mm Green board: easy to push and pull, no jam, no sharp scratch sound. Board frame material: high class ...