Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Doesn't fit eTrex 20

The eTrex 20 has a built-in rail, and this is a rail mount. Should be a no-brainier, BUT it doesn't fit without a separate adapter (which I haven't been able to find so far). Why does Garmin sell a rail mount that doesn't fit its own rail? Check fitment carefully - this was a complete waste of money for me.