Knog lights - kill them in the wet

have tried various different cateye ones - most use a knob thing to tighten onto seatposts. am curently happy w/a smart led light but it uses a bracket (but can also clip to bags etc) has anyone recommended the non-friction dynamo ones that run on magnets yet?

If you put on extra magnets it flashes more. Quite cool. Put a magnet on every spoke and you can get a constant beam if you go fast enough.