what is the difference between these two buzzers?
Both are 2300 Hz, and both are 85dB (i.e., same loudness) .  the Amazon listing makes it clear that it will activate with a DC 5V signal.  The mouser part has a poor data sheet, and it's less to me whether it wants a DC signal or a 2300 Hz sine wave to make it work, though I can convince myself that it works with a DC signal from the "operating voltage range" parameter on the pdf datasheet.