Over the past decade or two, Thermal Conductivity (k) has become a more popular way to specify thermal performance. While not as accurate in depicting specific thermal performance as Thermal Impedance (theta), it does have the virtue of being independent of part thickness. When possible, using the previous table based on Thermal Impedance (theta) would be more accurate, but if a customer is fixated on speaking about Thermal Conductivity (k), then this table will suffice.