The difference between engineer grade, high intensity, and diamond grade reflective sheeting.
Question: What is the difference between Standard Reflective (Engineer Grade or Type I), and High Intensity (Type III) and Diamond Grade (Type XI) reflective sign material?
Engineer Grade
Engineer Grade Reflective Sheeting typically meets ASTM D4956 Type 1 standards and is an enclosed film or lens using glass beads or prismatic optical technology.
This material is specified for use on non-critical street and road signs such as parking signs or wayfinding signs. It has less reflectivity than the other types mentioned in the original question.