Robotime-rokr mechanical wind-up clock timer pendulum clock lk501 that can actually work! A stylish spring-driven wooden clock with absorbing building experience. Put the mechanism together and watch how it works. Best gift kits and hobby for holidays and quality time.real peudulum: a gravity-swing pendulum with precise anchor escapement3 hours ticking: it can actually work for arounf 1-3 hours when finished!stylish outlook: appealing home decor for room or officechallenge your mind: fun of kits building & brain teasing of mechanical engineering