I wanted to get some breathable UPF pants for when I cycle on weekends and took a chance on these pants. I got the black pair size small.  The fit is perfect.  For reference, I'm 4'11" at 106lbs.  The only issue is that I'm not sure if this is really UPF 50.  It does protect against the sun, but I feel like it provides less protection than what the product description says.  I have two long sleeve rash guard tops from O'Neill rated at 50UPF for comparison.  I wore the top and this Cokar rash guard bottom on a 2.5-hour ride last weekend and my top half felt cool but the pant half was warm, which indicates the material isn't as good.  Both the top and bottom were black in color.  The material is thin and stretchy.  I think I'll keep these pants because they're affordable but will need to put sunscreen on my legs, just in case, for longer rides.  It's better to have some protection than no protection.  The desert sun is a killer in the summer here!