This kit comes with the usual "220VAC mains present" warning in the instruction sheet. I was therefore very surprised to discover a shocking (Pun intended) oversight in the kit contents. The largest component in this kit is the non-insulated heat sink for the TRIAC. When you consider that the heat sink will therefore be at 220VAC mains potential during operation you might want to include a TO220 Mica insulation kit for the TRIAC when buying this kit. Perhaps Yebo can include one in the kit?