Purchased 3-4 years ago and used several times each season. Very lightweight and easy for children to use. There is no size indication on the goggles themselves, so the exact size is unknown. The instruction manual states that the target age is S for 3-7 years old and M for 8-12 years old. Since a child with a large head circumference was using them, it is probably M. The last time (3rd grade) they were worn, the child didn't feel any tightness. Reference price: ¥4,400 (tax included) Worn with a knitted hat. I don't know if they are helmet compatible. Please understand. The lenses have some scratches, but it doesn't seem to have affected visibility. The noticeable scratches are shown in the images, so please check them. It seems the lenses didn't fog up much. The sponge has some wrinkles, but there doesn't seem to be any significant deterioration or peeling. The belt has hardly stretched, but the back of the belt is fuzzy. The anti-slip silicone doesn't seem to be very damaged. I'm not sure how to secure the belt after adjusting it, so I've sewn the sides to prevent the excess belt from coming out of the moving parts. Please cut and remove if unnecessary. There may be other oversights. Please purchase with the understanding that this is a used item. Frame width: Inside approx. 12.0cm Outside approx. 15cm Please allow for some margin of error. The item will be shipped in simple packaging. Please understand.