This is a listing for four pieces of ceramic insulation plates. They are to be mounted between the TO-3 packaged power transistors and the heatsink. They serve a good alternative to conventional mica or silicon pad, because of 1. their excellent thermal conductivity( better by more than 30 times !!) ; 2. their thickness. Since they are much thicker than normal mica plates or silicon pad, the capacitance formed between the heatsink( which is usually grounded to the chassis and the transistor is greatly reduced. This in turn reduces the parasitic elements relating to the transistor and improve high frequency performance. This is particularly beneficial for MOSFETs mounting. Thermal conductivity : 30 W/(m.K) Thickness : 1mm Air shipping worldwide is US$6.00 We welcome combined shipping. Powered by SoldEazy