I think it is this stuff:
Vehicle and Specialty Markings : 3M Roadway Safety - 3M US:****3M
3M has a lot of nice stuff. I personally like this one:
3M Light Management - 3M US: Automotive OEM: **** Automotive OEM: 3M United States
but haven't been able to actually find it on sale anywhere.
This would make for nice angle eye material, etc. etc.