Under ADR a Spontaneously Combustible Hazard Label must be 250mm x 250mm in size. The surrounding black border must be 5mm in width and spaced 3-5mm from the placard edge. Similarly, where a substance is packaged in a quantity greater than its limited quantity a 100 x 100mm UN warning label is required. These Hazmat labels must have a border of thickness no less than 2mm spaced 5mm from the diamond edge.