This is a 3 3/4 inch diameter brass disc that has a felt bottom. A felt "insulator' seperates the propeller like top from the brass disc base. There is a binding post on the base and a binding post on the propeller. The 6 tabs on the propeller are finger worn. When a tab is pushed down it completes the circuit and springs back to open the circuit. What is is thing ?? It was bought with a batch of telephone parts. I got it at the Antique Telephone Collectors Show in Shipshewana, Ind this weekend.

UNITED STATES Patented September 6, 1904. WILLIAM J. TONKIN, FLOOR-TREAD. Be it known that I, WILLIAM J. TONKIN, a citizen of the United States, residing at Ansonia, countyof New Haven, State of Connecticut, have invented a new and useful Floor- Tread, of which the following is a specification. This invention has for its object to provide a floor-tread adapted for general use, as under a mat to give warning when a door is opened or under a table or elsewhere to ring a callbell or other alarm; and my invention has for its object to produce an article of this character which shall be simple in construction, inexpensive to manufacture, certain in use, and practically impossible to get out of repair and, most important of all, which shall be so constructed as to effect an electrical connection when the slightest amount of pressure is placed upon any portion of the tread without regard to the direction from which the pressure may be applied ... etc ... etc ....