UPDATE: I was able to make contact with Siedlinar via email. They quickly responded, indicating that an update had been made to their product that included an adapter for 5 x 5 vinyl posts. They immediately sent a new set of lights with the 5 x 5 vinyl posts and insisted I did not need to send back the other set. Just installed them, and with the adapters they fit perfect on my posts. Lights are relatively brilliant and look nice. I'm very grateful for the prompt and friendly manner in which Siedlinar resolved this problem.Original Post: This set of 4 solar lights is advertised as "fit for 4x4, 5x5 vinyl posts and 4x4, 5x5, 6x6 wooden posts". It fits 4 x 4 vinyl, and adapters are enclosed for wooden posts. My posts are 5 x 5 Vinyl. I bought these in March of this year but did not get the posts in until September. Amazon shows return window is closed, and so far I've found no way to contact either Amazon or Siedlinar to obtain the correct adapters.Just added these to my deck and in the warm setting provide just the right about of light. When I have guests over and need more light I can move to the cool setting. Lots of pieces in case you need a different size. Some might get confused when they receive the package and trying to install on a composite 4x4 post due to the 3x3 option already added to the light. You must remove the 3x3 to install on a 4x4 but that was very easy to do.1st- These are very nice looking and have stayed on all night which I've never had with previous solar lights. I love having them on the top so their away from mowers on the ground. I love the look.2nd-the negative- we have 5 inch vinyl posts and the ads all say these should fit but when I opened the package the 5 inch adapter only fits 4.5 and the 6 inch adapter fits 5.5, I was still able to make fit.You have the option of sliding a switch to cool or warm. And who doesn’t want warm inviting lighting?! The manufacturer steps up if a light isn’t working and send a an immediate replacement. Order now! Fits every size fence post or a post alone. I live in the San Juan Islands that are not aways sunny- the solar capture is robust. They look like metal but are plastic and carefree- and protect the post wood. I am charmed.I got 8 of these & going to buy 8 more, they are a nice accent lighting Not to Bright so sitting out on my deck it's just enough lighting & doesn't blind you. I cut 4x4 post in 2" sections & glued & screwed to the 6x6 deck railing the put the lights on the 4x4 sections.These lights work for me, might not be as bright for some. Their solar after all, nice ambient light.One tip however, if the light is put in a place where it doesn't get much sunshine, no problem just twist it off its base and set it in the sunshine. You can also use it as a flash light in an emergency. I don't know how water proof they are, as we haven't had any rain.. I will not be leaving these out over winter.Great lights. Stay lit thru the night. Easy to install.They are built with quality and are nice looking they stay bright all night a great buyWe bought 4 of these lamps. As stated they are glass and very elegant looking. Easy to assemble. We had an issue with one of them not charging. We contacted directly to the seller and they were awesome. They refunded for 2 lamps and we re-ordered the replacements. They were quick to respond and solve the issues.I would definitely recommend these lamps and dealing with this seller.Cheaply made. Not adequate for 6x6 posts. They are too small. Yes they come with a 6x6 post base...but they shouldn't. Maximum post size for esthetics would be 4x4 and that pushing it. The LED light is just that. A tiny little light that looks like a speck at night. My picture makes them look full of light. But in the dark it's just a yiny little spot of light that gives no visual aid in the driveway.I waited for these for awhile since the first shipment was lost. Just love them. They are bright, sturdy and easy to install. Cannot comment on longevity since they have been working for only a few weeks. Definitely looking promising.Ces capachons sont très jolis et très fonctionnel. J'aime bien modifier l'ambiance avec l'option lumière blanche ou plus tamisée.as advertised, work great!!