Indoor and outdoor..
this thing ROCKS. it's still too cold for many SSTs in the outdoors in Colorado, and i have snuck it into some gym workoouts. A little breeze and it helps your sweat work better for you. normally, I am a sweaty, soggy mess after a run indoors-- there's no air blowing by and it's not a good sight. With this new T, I feel the cooling occuring and it let's me feel more comfy as i run. I can focus on other discomfort... like a knee.
GET ONE A TRY IT. you'll come back for colors