Pentel Wet-Erase Chalkboard Marker is suitable for use indoors and out. Semi-permanent formula won’t run off in a light shower. Remove with a damp cloth or non-bleach-based household cleaner. Writes on metal, glass and plastic, whiteboards and chalkboards. Valve-activated flow, no blobbing or leaking. Ideal for use on chalkboards and non-porous surfaces such as glass.