This is a superb little set of lights; they weigh around 30g each and are so small there is no reason to take them off the bike.
They are 'connected' so you can sync with your Garmin etc and control them that way. I must admit that I am a Luddite, and I just turn them on manually!
Speaking of which; as with everything modern there is a myriad of options (5 different settings in this case)...
For the front light:
Personally I think High mode is still too low for anything really dark and rural; so I have bigger lights for night riding on unlit roads. But these are perfect for telling people you are there (as opposed to illuminating the road) and thus saving the battery in your main lights.
The rear has the following modes:
There has been a real push towards riding with 'daylight running lights' - and I have become a convert. Having up to 12 hours burn time is perfect and means you can get away with charging twice a week, and simply being able to plug them into your computer at work, or any standard USB charger, makes them a doddle to keep topped up.