Any with a mesh side and UV rated. This Dorfman Pacific hat or similar is the style I always buy. Having the mesh in the summer makes a huge difference. I usually get mine from a hat vendor at the Mesa Flea Market who sells Dorfman Pacific hats, as well as other brands. https://www.amazon.com/DPC-Outdoors-Solarweave-Treated-Cotton/dp/B001AF15HQ/ref=cts_ap_1_vtp