Problem with the cheap Chinese knockoffs they tend to fail.I order a lot off MOSFETs and similar components for inverter charger repair jobs and then have returns due to component failure,not a happy experience when sailing way off grid.When taking a job I now cost Chinese/original with risks, advantages .Latest 20N60 batch received where second hand with new legs soldered on,the ingenious skullduggery will never cease to amaze me.