Too fast -- pretty dang obnoxious. Can induce fits.

I have three lights on my helmet -- two Fenix and a no-name. No-name has a fast flash but nothing like the Fenix. It doesn't induce spastic reactions. So I put it on blink.

The Fenix flashlights I either burn on medium or put on the S.O.S. flash -- much slower.

With both doing the S.O.S., I usually have one of them beaming at any moment, sometimes two. Rare instance when both are dark, the no-name blink provides adequate light for a second.

It helps that most of my route is over roads lit with street lights.

But I never use the Fenix in the hyper-flash mode. Too bright, too fast -- not very neighborly.

There's no future in causing blindness in those in command of two tons of steel.