This hat is a celebration of colorblending by combination of carrying yarn double and stranding. Marlisle? Fauxtarsia? Who knows? Because the stripes are so wide, size for children or smaller heads can be achieved by going down a needle size or two and getting a tighter gauge.

Note: When the stranding for color work happens in the same place on consecutive rounds, as it does with these stripes, it can be challenging to keep the float loose, even though it is only 7 stitches wide. Trapping the yarn in the same few columns each round also makes for a dimpled look. I found using the Ladder Back Jacquard technique useful for avoiding pulling in and keeping the hat stretchier. Two good tutorials: https://ysolda.com/blogs/journal/ladderback-jacquard-tutorial and
https://www.knitdarling.com/videos/Ladder-Back-Jacquard.