This accessory box contains 12 classic magnetic Magformers super triangles which contain free-spinning neodymium magnets safely sealed in every edge. The pack is the perfect stocking filler or birthday present for any child who has an existing Magformers collection. The pieces are four times the size of a standard triangle And help make mammoth structures, or add height to anything you're making. They are compatible with every Magformers set in existence. Other 12-piece box sets include squares, triangles, trapezoids, pentagons, rectangles, isosceles triangles, etc. - all the main Magformers building shapes.