- "The hat looked more or less like a baseball cap, except for whatever shining fabric it was made from — a fabric that seemed to change color every time the cap moved."
- —From Back to the Future Part II by Craig Shaw Gardner (quote, page 20)
The cap had an elastic headband, as opposed to the adjustable or Velcro kind, and was made of shiny lenticular material that changed color depending on the angle of the light striking it.
Emmett Brown had purchased the cap, along with an auto-adjusting and auto-drying jacket, before travelling from 2015 to 1985 to pick up Marty. Both items, along with a pair of Nike MAGs, were produced by Doc from a large futuristic Nike Footwear bag he carried aboard the DeLorean time machine.
At the Cafe 80's, Marty threw the cap on top of the Wild Gunman video game before playing it, then realizing that he needed a cap when taking the place of his son, he took Marty Jr.'s cap off his head and put it on his own. He threw this cap aside when he got angry at Griff Tannen for calling him "chicken".
- In 2009, Nike released a cap like the one seen in Back to the Future Part II, but its colors were not similar to the movie. They also made lenticular shoes and another cap with the word "AIR" on the top using the same colors. A couple of years later, Diamond Select released a higher-quality version of the cap with movie-accurate colors.
- Although the cap exists and can be bought from Amazon.com, as well as outlets such as comic book shops and specialty stores, it's not something worn all the time. Unlike the cap worn on-screen by Marty and Marty Jr., which has an elastic headband, the cap available for sale has a Velcro closure.