This is the thinnest jacket sold by Montbell. I purchased it at a Montbell official store. The fabric is thin, so it doesn't provide much warmth. I used to wear it when hiking or doing outdoor activities on chilly days. I haven't used it very often, but I've had it for several years. It's size 100, but I could also wear it when I was size 110. ↓ Product Description This windbreaker is compact and easy to carry. It's lightweight but effectively blocks the wind. It's a pocketable design that can be stored in the left pocket. #Montbell #Windbreaker #KidsClothes