I think this is the most useful use for one I've heard so far, but when I think about how often do I need a little plastic knob - maybe once a year? I'm sure a

I think this is the most useful use for one I've heard so far, but when I think about how often do I need a little plastic knob - maybe once a year? I'm sure a couple of shops could do this as a business but other than that it seems crazy to think people will buy these things en-masse for homes.