Always On.
If you don't like to run those ultra long dildo lights on the front or rear of your bike well don't. They fall off in bunch rides, they look ugly and get in the way. Don't. Stick these in place of the standard plastic bar caps you find on every type of road bike. It has a wedge which expands with a CNC cap that houses the LED light. One press turns it on, 2 presses for flashing and 3 to turn it off.
Once the sun rises up then turn them off and you don't need to look at that unsightly extension on the top of your handlebar. They're light and always with your bike, batteries are cheap and offer good light coverage at the widest part of your bike.
Comes in few colours if you need to match your shit.