These work. They are warm for the first few minutes, but as soon as you start to sweat, they actively cool you. Much more comfortable with these than without these on a 90 degree day.

These are solid arm covers. They breathe nicely, but the black balances that out on bright days. They slide down during MTB rides--could be that my delts need working out, but they do slide despite being a good fit elsewhere on my arm--perhaps a touch of that silicone banding at the top would help? Ultimately I use these to protect my arms from poison oak and the sun and they work great!

A little thicker than others but actual do not feel to warm. Year round arm covers.

Great protection from the sun, and fits perfectly!