Review on 👕 Optimized Bodtek Boys Thermal Underwear Set for Boys' Clothing by Douglas Davis

I like this item but seller should clearly state what is small, medium, large etc. I bought the L size for my son who is 10 years old and weighs 75lbs 4ft 5in and thought he might be a bit big so he could grow into it. The size on the product when I received it said 9-10. Why couldn't they put it on the side so I know what "big" means. I would buy Xlarge. Luckily it's thin to fit in a shirt, haven't tried pants yet.