These lights are pricey, but worth it. I put them on tip-ups set up about 120 yards away from my lake cabin, and I can see them at night through the cabin window no problem. Really makes ice fishing more pleasant. The main flaw I see with this light is that the bottom is screwed on and off both to turn the light on or off, and to replace the batteries-- there is some potential to accidentally have the batteries come out when trying to turn it off. A trick: if you're doing this, place one of those inexpensive green glowsticks on the snow next to your tip-up. This helps you see where the tip-up is so that you know where to look for the flashing red light indicating a fish, and also keeps snowmobilers from running your tip-up over.
I've done my research on tipup lights before i made the decision to buy these. They are the best! The switch will only activate at approximately a 90 degree angle, so they work great on the polar style tipups as well the lakers, which i use. They are very light so they won't weigh the flag down so it won't stand straight up. They have a screw on or screw off type switch within the battery cover. So far no issues other than to change the led color so that i can know which ones are mine when fishing with multiple people!