I like to wear caps under my helmet for the shade provided by the shirt brim, but it's hard to find caps that also assist with managing sweat. I avoid cotton caps for that reason but seems they are the most prevalent type offered. This Assos cap is great - the short bill provides some shade, the cap itself wicks sweat and is thin enough that I don't have any for issues with my helmet. Importantly, the cap stands up well to machine washing and air drying.
Large enough for my 7 1/2+ noggin. Most caps shrink and become too small. This, I hand wash and dry. No shrinkage. Sturdy brim flips up when necessary. Cap is perforated fabric for hot summer days. I bought every color. Finally a 5 star Cap.