EU size for kids?

[Glendon Mullins]

Trying to find my son a pair of boots, he wears size 7 or 7.5 with thick socks for hunting etc. I found that LOWA is having a pretty good clearance sale for kids, but their sizes are EU

so what size in EU equals a 7 or 7.5 in US lol?

thanks in advance to those smarter than me