Bests & Worsts Reviews from Amazon

Each time you push the on/off button the setting changes - it rotates through 4 settings- OFF, 4 LEDs on, 24 LEDs on or 28 LEDs on. The light is a bright white, which is exactly what I wanted.. To attach the device to the umbrella pole, you have to open the device. There are no written instructions for opening the device and it is not intuitively obvious. Actually, it was counter intuitive to me. There is a latch which looks like a sliding button, but it does not slide. You have to pull it out and that will open the device so it can be attached to the umbrella pole. It is easy to operate once you know to pull rather than slide. You can leave the device on the pole when you crack down the umbrella. When I crank the umbrella down, the umbrella "runner" pushes the light down the pole. I have no problem leaving the light on the pole and tying the umbrella canopy down. When I open the umbrella, I do have to push the light back up the pole. Some reviews said that the light was always on. The "on/off" button on one of the two devices I bought was broken and did not contact at all, so when the batteries were installed, the lights were on. Removing 1 battery turned the light off. I contacted the Seller and they are sending a replacement for the broken device. The other light worked as designed. The plastic switches may be the weak link in the device. I noticed many reviews complaining about not being able to turn the lights off and based on my experience presume it may be the button. The seller was quite willing to replace the faulty device. I expect to buy more of these lights when I buy more umbrellas. I may even use them elsewhere in the yard - they work even without an umbrella pole! I will recommend these to friends as well. 5/21/2018 Update. The seller promptly sent the replacement light, but I was unable to try it until tonight. It works perfectly. And it is definitely bright enough to read by.