Comprised of a cylindrical copper rod with its one end surrounded by a steam of water flowing through a spiral tube provided at that end. Fitted in wooden case lined with felt. The front portion of the case is removeable. Without thermometers or steam boilers.

1. Size of rod 30cm long 1.8cm dia
2. Size of rod 30cm long 2.5cm dia
3. Size of rod 30cm long 3.7cm dia