They are made of wood and clack on the sidewalk or street. I went to a spa with my colleagues in Japan. It was a two day binge. The idea is to get so drunk that you tell your boss all the things that have been bothering you in the past year. After a sumptuous dinner and a dip in the spa, we all went out for a midnight bowl of soup at a nearby ramen stand. All of us were decked out in light robes, clickety clacking our way along except for the foreigner who couldn't get the hang of it.