Small old wind-up alert or alarm bell. Twist the metal dome clock-wise to ready the bell. Press the little lever at the base of the plastic (Bakelite?) mount to trigger a loud clanging. Works quite well. The plastic mount is missing a couple of pieces along the right edge. A repair has been made to the round protruding part under the bell. Measures 6 1/2” long and 4 1/4” at widest. Weighs about one pound.