Complete TO-220 heatsink mounting kit for efficient heat conductance between heat sink and TO-3P TO-247 TO-220 power semiconductor packages. The package includes the silicone thermal conductive pad together with mounting hardware: M3 Screw + Washer + Reinforced Fiberglass Bushing. The appropriate size of the thermal conductive silicone pad highly improves the heat transfer between the device and the heatsink. This pad is electrically non-conductive to improve the safety of the device by preventing the possible short circuit. This mounting kit is for cooling TO-220 TO-247 and TO-3P power semiconductors packages such as MOSFET Transistor, LM317 and LM7800 family etc.