It consists of a brass ball of different diameter, secured to amounted brass ring by a chain.
It consists of a brass ball of different diameter, secured to amounted brass ring by a chain. The ring is mounted on a brass rod with a superior quality wooden handle. When both ball and ring are at the same temperature, the ball passes easily through the ring. When the ball is heated, it will no longer fit until cooled or until the ring itself is heated.
Diameter of Brass Ball is 18mm