If you've thinking about using these, you'll have to wait a day to use them. What a surprise! They aren't useful.I thought these would be useful for traffic control in emergency response: I'd put them in places to get drivers' attention in advance of a control point. It turns out that you can't turn these off. So normally, I'd have these stored some place (and charged) ready to go. But not so: they will NOT be charged. So the night I decide to use them, I won't be able to use them, I'll have to See full review