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I was browsing around on Youtube yesterday, and found some videos about this little stroke of brilliance. Probably the greatest idea ever. IDK though, $10 seems awful steep for what's basically a little piece of plastic. I would think you could just tape some scrap wood/plastic/whatever you have lying around for the same effect. Still an awesome idea though.
It's a nice idea, but you have to be really light with your feet to achieve what are you looking for