In Great Britain, every shot firer is provided with a scraper for cleaning out shotholes, and in safety lamp mines a break detector must also be provided. The two tools are combined in the scraper and break detector. It can clean out a shothole and detect breaks in the walls of 1/8 in (3 mm) or more in width. The firing of a shot in a hole traversed by a crack exceeding 1/8 in in width is forbidden.