Sonic products seems have issue with durability, over 10 years, 4 Sonic products have been broken after used for one year, so I don't put Sonic products in checked baggage and I already know that Sonic products likely to fail on arrival after rough at airport.
Right now, I have Sonic Alert since 2013 and don't have issue with it, but I don't like "Slow" and "Fast" button. I prefer "HOUR" and "MIN".
