I tend to like peaceful, high quality Chinese infiltration. I am less keen on some US infiltration such as Microsoft, and stuff I would only post on the politics forum.
Thank you
Bald Paul for the radar. It was mentioned
above by
The Chemist , but I only (US) Googled it when I saw how small they are.
The Garmin Varia appears to be expensive here on amazon.co.jp. But there is an aliexpress Second Hand (?) perhaps refurbished ("98% new") version only aliexpress which is quite reasonably priced.
https://www.aliexpress.com/item/1005003671393369.html
And there is a Chinese version at about the same price
https://www.aliexpress.com/item/1005004540845201.html
Still both are nearly half the price of one of my bikes and neither of them bleep I think. I would a radar to warn me when a car approaches without having to get a bike computer. I wonder if there is a bleeping rear radar.