Warning Signs are crucial in preventing accidents as they offer drivers advance notice of changes in road conditions, giving them time to take appropriate action. All black and yellow warning signs are available in Engineer Grade, Prismatic High Intensity or Fluorescent Diamond Grade. Please reference the sign code, sheeting type and sign size when ordering. Standard aluminum thickness is .080ga. Other thicknesses can be ordered upon request. All signs are made in Madison, Wisconsin using 5052-H38 alloy aluminum and 3M reflective sheeting.