3.0 Duramax Diesel fill cap

Simple fuel cap to help prevent filling fuel tank with DEF.  After my buddy destroyed his 2500 HD from doing this very thing, I thought to make this to help prevent the same accident.  Others are available on Amazon etc.  This doesn't have O-ring seal or anything.  Just a simple slip fit.  I had to enlarge to 100.75% for my Yukon 3.0.  I used the slicer to add words.