San Diego State will wear these sick helmets this year. 👀 Tremendous look for Aztecs h/t @PrepSportsPlus pic.twitter.com/U9wcHkMXW2— Brett McMurphy (@Brett_McMurphy) August 23, 2021
From an article headlined, "A Deeper Look at the Sickest Helmet in College Football":
The design is actually hydro-dipped into water. The helmet is painted red initially. Once painted red, the Aztec print is laid upon a tank of water. Each side of the helmet is then dipped, one side at a time.