A winter hat worn with the edges unfolded such that an excess of of the hat's material rises above the wearer's head, resembling the reservoir tip of a condom.
The term is often used as a shorthand identifier for the typical varieties of neon adorned "steezy" snowboarder bros who tend to be the primary exemplars of the fashion.
"Did you see that posse of reservoir tips that just climbed out of that Honda Civic?"