Siedinlar Solar Post Cap Lights are easy to install - they come with different adapters and a set of screws. I installed these lights on 5x5 vinyl posts using one of the provided adapters. I did not use provided screws since they were generic metal screws which did not match white color of the posts and lights. In addition, they were too long for vinyl posts. I used instead short white hex screws used to secure gutters.The lights are not overly bright, however bright enough, especially when it is completely dark outside - comparable with similar lights from other vendors. Unfortunately the batteries in these light do not last very long. By 3:30AM-4AM the lights go dark.Wasn't sure about these but am so glad I bought them. I only purchased 2 for the bottom of my steps and love the way they look. Haven't had them long enough to comment on longevity, but the price point is worth the experiment. I used the warm setting and like that a lot. They fit perfectly on my 4x4 posts (once you take out the insert). Make sure you turn them on!I bought two of these for the posts on my deck to provide light for the steps. They provided a nice amount of light so I recently bought two more for the other posts. Now I have plenty of light when I go down the steps to take the dogs out at night. They are dependable - lighting up as soon as it starts to get dark. Theylook good and are a nice match for the white vinyl posts on my small deck. They are easy to install and they seem to last a good while. They are still "lit" when I go to bed around 11 in the evening, Great for safety reasons as well as being a very lovely addition to my deck!The lights are gorgeous and admired by many passerbyers. I love the ease with which they are installed and the optional cool and warm light. When there was a wee blip in the order, the company was very quick to remedy the problem. Excellent customer service. Would highly recommend them! (Can't yet comment on longevity as we haven't had them long enough but I am very optimistic they will serve us well for a long time)What like the look of them. We have them on our fence postsWorked fantastic over Trex railing system. Only problem was that the lights are true white while the railing is a softer off white. Took the lights apart and spray painted them with Rustoleum Aged Copper. Perfect compliment to the Saddle colored decking and offset the white of the railing!These lights fit perfectly on my 4X4 Vinyl Posts as you can see in the pics. They were super easy to install. The lights are not super bright but they give off a nice light as you see. I bought them bc the lumens were supposed to be brighter, as you see judge for yourself this was after a full days charge of sunshine on the cool setting. The price for two was reasonable and it was all I needed. There are multiple adapters in the box for your specific needs. I don’t know how long they will last that remains to be seen, hence the 4 stars. The glass insert is a plus and it looks durable. Everything you need is included, I’m happy I purchased them.These cap light look fantastic day and night. Very bright on white light. Lights up my porch without using electricity. Lights last all night till sunrise. Can't speak to longevity yet, have only had them 6 months.They give off a lot of light and in the spring/summer stay on all night to morning. Give a really nice glow to the back yard. You can choose bright white (blue light) or warm white (more yellow light). I chose the warm white and it looks really nice. They are even lighting up in the winter even tho there is snow on the charging pads, just not staying on through the night. But, still happy with the purchase and definitely recommend!Though advertised as a "fit" for 4x4-inch wooden posts, it is not. Without the 5 inch or 6 inch adapter, the "default" mount contains an underside that isn't flat and doesn't sit flush with the wood. Instead, it is wobbly. Even if it did, there is still a sizable gap where the mount meets the wood. Though the product is well-built and of great quality, it is not at all a good purchase for the 4x4-inch wood post.These fit out 6 x 6 posts well. Well made and very pretty. Nice warm glow. Now to see if they last as I just installed them yesterday. Very easy to install. Has two light settings so that's a nice option and I like that they are glass and not plastic, gives them more weight.Listed as black powder coated, led me to believe they were metal. The housing on the lights is plastic.Nice product. Plastic body, glass windows. The fact it is oversized for the post looks intentional and isn't a problem since you screw it in from on top. Rechargeable batteries are great, they are still going strong when I wake up in the morning (8hrs)