I now have 3 bikes, 3 B&M top mount Line tail lights. they are dynamo but the battery version has 1 AA along the bottom/..
Took off a 4D senso + the same light minus the + leaves off the power tabs. wired, in off position ,.. on the switch, is run without standlight
without the dynamo power It's just Off. middle position is On..
On senso mode 3rd switch position, it's off in daylight but will come on going through a tunnel, then turn back off on the other side/,,
Motion detector .. even if left in senso mode will turn itself off in the dark when parked, in a minute or 2..
'Permanent' model just on & off.. 2 positions..
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