Magnetic whiteboard with aluminum frame. Write or draw with dry erase markers, or use as a magnetic bulletin board to display papers. The dry erase surface is guaranteed not to stain. Numerous sizes of this whiteboard are available; check below for options. These whiteboards are commonly used in classrooms, offices and other areas where presentations are made. Large whiteboards, 16 feet wide and 20 feet wide, include two sections joined by an H channel. Buy with our clip magnets or button magnets. This marker board, in the 4×6 size, is our most popular.