If you have a head size of 6 7/8 or smaller ,the s/m/size will be to big...,very bummed...need s/xs size. Still a great looking hat and looked well built.

I have a big head, I max out pretty much every climbing helmet I have tried on. Got the L/XL and it fits me well. A bit snug but way better than any other i have worn. It has a small pad on the forehead that works well to absorb some sweat. Does not dry quickly but keeps its shape when wet. Got hailed on while wearing it and kept my face nice and safe.

The front top of this hat fits rather weird. Instead of going with the curve of my head in a round fashion there's a steep peak at the front, giving the hat one of those 'hats with spinning propeller on top' looks. Probably mean I won't be wearing it much.

Fits great but had to return the first one because it was too big. Usually wear a 7 1/4 and the large was too big. It is a heavier material and probably won't be wearing it this summer when it's warm but the rest of the time it's my go to hat.

Being the Mammut fiend that I am. I am going to rant and rave about this hat. I purchased this hat in the Oak color and it has been a great all around hat. I have worn it around town, and also to the field. It is a little thicker for a summer wear hat as mentioned already, but it fits great, and break in was fast. Love the mammoth logo as well as the soft material.

this is a six panel hat and yes, it's thicker... not exactly a hot weather cap. but i'm a fan, it has a shape that isn't completely round on the front and it looks pretty sweet

I returned this hat due to the material. It has a very thick/heavy feel to it, almost like a corduroy type material.

its a hat. looks good, fits good.

This is a first rate hat. Excellent quality. A very sturdy brim that held together when it got soaked from a recent rain storm. Wore it at the local Marketplace and got quite a few people asking about the logo. In one instance it worked to my advantage since the shop keeper started asking about the logo then filled out my order ahead of a few other folks.

The quality of this hat is awesome! It has a really thick and strong bill and the red goes great with most stuff....