This Item Is Used For Comparing The Thermal Conductivities Of Aluminum, Brass, Steel, Nickel, And Copper. The Unit Comes Assembled And With A Supply Of Wax. Includes Activity Guide. This item is used for comparing the thermal conductivities of aluminum, brass, steel, nickel, and copper. The five radial spokes are attached to a brass hub. Each rod is marked with the metal name on the hub. There are notches in each rod to hold a wax pellet. The unit comes assembled and with a supply of wax. Includes activity guide.