It is used to compare the thermal conductivities of different material. It consists of eight different rods having length 30cm.
Glass dia. 3mm – 1
Aluminium dia. 3mm – 1
Copper dia. 3 & 1.5 mm – 1
Brass dia. 3 & 1.5mm – 1
Iron dia. 3 & 1.5mm – 1