Once you learn to use it - works great! Great value!

I'd been waiting for my old, trusty more expensive and battery sucking light to die so I could open this one as I'd heard and read great things. The day came and I eagerly opened it up aaaand nothing.
I figured it sat a couple weeks - eh about month and a half - two months on the long end let's say- so I unsealed, peeled the stickers off of and inserted two new batteries from a new pack (a pack from which the other batteries I had already used so far in other items around my home with no problem- they all worked fine so not a bad batch of batteries
And nothing happened.
I made sure the coil and metal clip were in their places just-so and didn't need adjusting, I tried slipping a corner of paper in the backing thinking maybe it was too loose and that like I've fixed many a things in the past in a pinch using the same methods, it would add the extra pressure needed to keep batteries holding snug and in contact with the approximate points of contact.
But no. I'm so frustrated. I bought a bunch of these for gifts and personal use but now after the very first one is bunk and the second one did the same thing (though it did turn on and work faintly for a few minutes before dying), I am not going to tear open 10 boxes just for myself to find the one that makes it worth it or risk giving these junk lights out as embarrassing gift fails.
Super disappointed and too late to get a refund on Amazon.

Is there a way to replace the battery. Please advise.

Bright emitting light strobe with a simple touch of a button...

Light and compact. Easy to clip onto the back of my hat for early morning runs. Thank you!

I like it - compact, the strobe works well.

They really, really, REALLY need to make it clear that you need to hold the button for 5-8 seconds to turn it on. I'm used to devices and lights that you turn on with a "press and hold" on the power button, and I thought mine was defective, because I wasn't pressing and holding long enough. Press and hold until it turns on. Upside is I got my book lamp running again with the batteries I bought for the Nathan.

The light and electronics are sealed, good for being weatherproof. 112 hours on strobe is great, but you will trade compactness for having to buy 2 of the more expensive 2032 coin batteries.

Light functions as should and is bright enough for traffic to see.

Showed up with dead batteries. Although on clearance, defective merchandise shouldn't be shipped to customers. Sent in a follow up to customer support - crickets.

Perfect little safety device. I do wish that there were directions, as they are not intuitive to use. Press and hold the power button for 5-8 seconds to turn on, and same to turn off. Most folks will simply assume tat their new light is defective instead of pressing and holding the button down for 8 seconds. Set it on flash and it is easy visible in the dark from a quarter mile away. Put one on the strap of your running cap, and clips second one onto the front of your collar, and your protected coming and going.

Stopped turning on after less than a month. Maybe just the batteries but a pain in the butt none the less