I'm not sure how I would tell just by looking without reviews and specs, any more than I could tell from a picture, the differences are really subtle. The plas

I'm not sure how I would tell just by looking without reviews and specs, any more than I could tell from a picture, the differences are really subtle. The plastic cover on a bad switch looks an awful lot like the one on a good switch. Glass filled nylon seems to be somwhat reliable thought, not quite as much utter trash has a chassis made of that, at least for tools. And sheet metal, I usually assume anyone who uses that is cutting corners or wants to appeal to old fashioned types who hate plastic no matter what.