Leather. Chocolate covered (no – coloured). Comfortable as slippers for the first ten miles. Like wearing two lumps of wood for the next five!
Sadly they only lasted 500 miles. The soles were fine, but the leather – despite dollops of Dubbin – cracked and broke. I continued to wear them, but they were no longer waterproof and, after one soaking too many, I threw them out and brought some fabric ones instead.