The sole is low-heeled and usually of crepe rubber, stitched-down to the upper.
From the en.wikipedia.org
They ALWAYS have crepe rubber soles.
From the charlotteobserver.com
Replacing the original crepe sole with a more hard-wearing, non-slip rubber one, the result is a very pleasing boot that bridges the sizeable gap in the market for casual winter footwear for boys.