Wood Metal Cylinder - Standard

Comprising a cylinder, one half of which is polished wood and the other half metal. If paper is wrapped tightly around the cylinder and the rod is held above the flame, the portion in contact with the wood will be quickly scorched while the portion in contact with the metal will remain uncharred, showing the differences in their respective thermal conductivities.

Q = What are the dimensions?
A = 200mm long x  28.5mm diameter. Brass part has 1.5mm thick walls and is 100mm long.