A warning apparatus is provided, whose main body includes a monolithically formed transparent tempered material with a thickness. The top of the main body includes at least two injections units. The injection units are upward bumps. The injection units are less than 10 mm in height. The curvature on...http://www.google.co.uk/patents/US20080101859?utm_source=gb-gplus-sharePatent US20080101859 - Warning Apparatus
