The mechanical equivalents of these shunting signals are found as miniature semaphores (the arms are the same size as those of permissive signals) and disc varieties (the disc is about 12 inches/30 cm diameter). The small-arm semaphores are painted in the same way as a full-size stop signal, while the discs are painted white with a red horizontal band. A small-arm semaphore shows "clear" in the same way as a full-size stop signal, while a disc rotates through 45 degrees or so when pulled off so that the red band is angled. Both display small red or green lights by night.
