this alarm clock, by industrial facility, is designed so that the whole of the back casing is the actual bell that rings. industrial facility say that this improves the efficiency of the clock, using fewer components and creating a louder ring. it was designed for the japanese brand IDEA, and comes in three colours, each of which is inspired by a loud object: a fire bell (red), bicycle bell (chrome) and door bell (black).
simple, clever thinking. and they look good too!