Simon Mason wrote:

QUOTE:
Over the years, several brands have created products designed to provide cyclists with a clearer view of what's going on behind them.

So far none of the options has been successful enough to become a widely adopted market leader - think Garmin to cycling computer
as Hoover to vaccum cleaner, though the GPS brand's reign is less secure these days.

https://www.cyclingweekly.com/news/p...l-safer-456396

"vaccum"?