Material: Shield signs are offered in aluminum and laminated plastic labels, while regular signs are available in engineer-grade reflective labels, laminated plastic labels, 40 mil aluminum, plastic, engineer-grade aluminum signs, and more options. Impact: With a different shaped sign, you can convey any message effectively because people pay more attention to them and read the sign carefully. Visibility: By looking at the shape of a sign, pesticide applicators can understand that the land is a “No Spray Zone". Even if drivers face the sign from the back, the shape will grab their attention.