Obviously not like the old chocks where you could take a big marker pen and write your 'N' number to deter theft and identify a specific aircraft. Material with company information embossed on the ledges, making marking doubly difficult as the information embossed and the nature of the rubber composition do not favor a quality permanent marker. so the letters are all black. If I had to do this all over again I would just go to Home Depot and buy some lumber and cut it to L 6" X W 4" H 1.75, paint them white, label them with black marker and poke a few holes in drill each of them to tie them with nylon cord. There is a business opportunity here for making wooden blocks for people with chassis, wheel covers (pants, gaiters, etc.).