I believe this is a throttle valve box for a railroad engine. Not positive. Don't know if the throttle valve is that small. Maybe you railroad gurus will know. Allow the photos to be the best descriptor of this item. Additional pics or questions welcome and encouraged prior to purchase so we both arent inconvenienced with a return. If you purchase this item and feel like it was misrepresented I have a 30 day return policy. Thanks for looking.