This item is used for comparing the thermal conductivities of aluminum, brass, steel, stainless steel, 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. 

Shipping weight: 4.45 Oz., Dimensions: 14" x 7" x 1".