For footwear and tire track impression comparisons 0.040&';&'; thick Rigid vinyl plastic These scales are designed primarily for footwear and tire track impression comparisons. They are excellent for verifying perspective distortion. The scales are printed on rigid vinyl plastic and feature exceptionally sharp division indicators. They also feature a glare-free finish for photographing in most lighting conditions (0.040&';&'; thick).table.productattributes, .productattributes td { border-bottom: 1px solid #ddd; border-collapse: collapse; padding: 2px; text-align: left; }