the sheet keeps the room dark like 95% all the way, but the suction cups don't work. I just used my windows top half to hold the sheet in place. I'm happy with this purchase.The biggest gripe I have is with the fact I ordered a pink one then got a black one and had to go through the returns process to get the correct one.It blocks most light from entering, but it will still allow some in during noon while I’m in a wooded area with a small window. Basically, I wouldn’t expect it to stop the big windows from shedding light. Suction cups don’t work on straight dry wall. I do like this though as it wasn’t too expensive and is able to fit most windows and it looks so cute and adds to the vibes of my room so much more.Bought this to put up over my window after working night shifts and it has worked great!! It makes my room so dark even during peak daylight. I would give five stars but sometimes the suction cups are not the best and they would unstick, but after repositioning it normally it works for meThe black curtain works well. There is still light that comes in around the edges, but the blue curtain (not sure about other colors… I have black and blue) does not block light totally. It is definitely dark but still “glows” with sunlight shining through. Black gets 5 stars! The other ones… not so much.These were perfect for our windows when working nights and have to sleep during the day. The suction cups worked great on most window surface. It also comes with Velcro for textured glass. The curtains are lightweight but completely block the light. I also used them for when our infant grandson is visiting to keep the room dark during nap time.This is a great product to have if you travel a lot! A lot of places don’t have black out curtains so it’s good for naps and also nighttime sleep! I’d definitely recommend.It’s over priced but it does keep the sun out for the most part. It’s shape for a more rectangle window and mines is super long. If you can sew then save yourself moneyThere are a lot of mixed reviews and I was nervous about this curtain but I got it for my bedroom because I have a projector and wanted to be able to see the screen clearly even during the day and it works great! The curtain is not sheer at all, I love the ease of putting it up (the suction cups work great) and being able to take it down when I don’t need it. It was worth the money.I'm renting a room with white blinds currently, so can't really change anything about this room. These blinds are great for summer, when it starts getting light earlier. They're really good material and block the light out so well. Really impressed with them, and they help me sleep so much easier in a morning. The suckers stick really well to the window.2 sides have loads of suction cups but the other 2 have at the most 3 so unless your window is exactly the same measurements as this blind it's fairly useless. When you're on a smaller window you put on what you can but you're left with big gaps where the cheap material just flops down and there aren't the suction cups nor velcro to manipluate it. Annoying and simply poorly designedIve put two stars as the curtain itself at the end of the day it does something, but there's quite few wrong bits with it.First of all, if you get it in blue forget about that deep dark blue as what you'll get is a light blue sky kinda colour - still does protect from light, yet not even close to what advertised. Suction power is not extreme neither: I've managed to keep it on the window, yet not thanks to the suction only. Regarding the fact that is portable yes, I guess that's good. As said, it does the job, but at for couple of pounds more you can definitely find something better (and with the colour you really want!).So Very Pleased with these Blinds that I bought two, they are thick enough to block outAll light, even the street lights, house lights & the very annoying sleep depriving on all nightvery bright security lights!I found them to be a god send for blocking out unwanted artificial night light! Also Very cooling in the summer for blocking out heat from the sun,sprayed the suckerswith water & they stuck on the window & my painted wood frame without any problems,I would suggest pulling the blind a little tight at the top with no gap at the top beforesecuring sucker to stop the blind sagging at the top! The suckers last quite a while beforethey need respraying too! Fast Delivery would recommend Many Thanks.Material definately blacks out, some of suction pads were bent on arrival and I used hot water as suggested to try bring back to shape, some worked but some did not and stayed bent and did not have any suction power! I've played around with the whole curtain and is doing the job I obtained it for but I think the mfg should consider using a different type of suction pads or protect them during transit!