MASSCOOL Thermal Cooling Grease (STARS-420) MASSCOOL Stars-420 Thermal grease, White grease. MASSCOOL Stars-420 Thermal grease, White grease, Dimensions: 55x 5 x 5mm, Color: White. Specification: Specific Gravity at 25 Degrees': &gt;2.8, Dielectric Constant:&gt;5.1 at 100Hz, Dissipation Factor: &lt;0.005 at 100Hz, Temperature Stability ( Degrees'): -50 ~ 300 Degrees', Thermal Conductivity (W/m-K):&gt;2.062