Rtl510
I used a Lezyne Zecto Drive 80 for quite a while, and was happy with it. It's very bright even in the daytime, and easily holds enough charge for a 5 hour ride on flashing mode. However, last year I switched to a Garmin RTL510 radar light that I got on sale. Best accessory purchase I've made. It's expensive but worth every penny. At my age (old!) I have limited neck mobility and shoulder checks before left turns are literally a pain. I still try to take a quick look, but have found that the indication of cars behind shown on my Edge 520 is very reliable. Also, on busier roads, cars whizzing by at high speed are no longer a surprise. Riding now feels much safer.