FENICAL 26 x 14cm Erasable Hanging Chalkboards Rectangle Blackboards display for Message Sign Colour: Black. Material: MDF. Dimensions: 26cm*14cm*0.5cm. Attached to each mini blackboard is a hemp rope so it can easily be displayed anywhere. These chalkboard are erasable only for regular chalks makers! And we do not recommend the use of liquid chalk to write on.