The material is very soft and breathable. Not as lightweight as I thought a bio dry tee would be. The softness and bio dry make up for the lack of lightweight fit. My kid played outside all day and the shirt is breathable

These shirts are SO SOFT and plain colored which is a huge bonus. We dislike all of the logos and characters. My son is a true size 6/7 and we went with a Medium and I'd say its perfect. I would size up to give some room for growth.