4″ high x 1/2″ deep. Steel body. Steel shackle. The key is not original. The round shaft bypasses ward(s). The 2 prongs at the end of the key engage a spring loaded bolt. The shackle is secured when the bolt is in the verticle position. This mechanism is warded and functions the same as “BULL RING LOCK PAT.28871-12” #5153 which has a lever mechanism to depress the spring loaded bolt.