3M Scotchlite Reflective Safety sticker
This Hardhat sticker is cut-to-shape and made of. With the standard of 2.5 inch Diameter so it is seen from a far.
Note: for over 40 years, the size of the command stickers had been 2.5.diameter.
The 2.5 inch size came in to use because the print shop, was asked to help fix the problem with the sticker coming up and getting dirt under the sticker.