I used Neon 5x before with bad results. It had a funky smell. The cans were predominantly black with some flame decorations. I was very surprised because I had tried before with just "Neon" a yellow can with red text, and the results were not bad. So I figured Neon 5x would be better but that turned out to be wrong.
The manufacture date codes, along with whether the product contains odorant/mercaptan can be found at the head post.
The recent Neon 5X is exceptionally clean, clear, and sweet (neutral to the nose.)