Thermally conductive solid silicone is an unsupported silicone rubber.  This material offers thermal conductivity along with electrical isolatin for heat transfer between PC boards and heat sinks.  Thermally conductive solid silicone is a firm interace material used for applications requiring a heat protectant.  These products are designed to remove the heat generated by an electronic device to the ambient environment in order to ensure the reliable operation of computers, communication equipmment or similar electronic hardware.  It can also be used for filling air gaps under high load force between PC boards and heat sinks.

Thermally conductive solid silicone is available in a light blue color and is formulated to provide clean release from most surfaces.