We have two Pekingese. For the uninitiated, they're dogs. Small dogs. Very small dogs, in fact. They both love going out on the porch. To bark. At squirrels. And anything else that moves. The problem is, more often than not, they want to come back into the house right after they've gone out. It's a rule. And after they've come back in, they want to go right back out. That's also a rule. They're ridiculous beasts, to say the least. But also cute.During the warmer months, we will leave the porch door open to help the hell beasts move between realms. We have a door screen that self-closes in the center with magnets so that the dogs can push their way out and push their way in as they see fit. It works great and they both make liberal (oh stop, this is about dogs, not politics) use of it.During the colder months, however, we are at the mercy of their whim, letting them out while keeping the door open just enough that they can push their way back in. The drafts are annoying, and once they've pushed the door open to come in, we have to get up to go close it again...or to let them back out. This would go on all night. Because we have no willpower. And because the annoyance of getting up to open and close the door was still less annoying than having a dog pawing at our legs all night, wanting to go out.Then we got an idea: what if there was a pet door that could be installed in a window...like one of those dual fans? If I've learned anything over the past 15 years, it's that if you can imagine it, someone is already selling it on Amazon. So, I confidently searched on Amazon. I don't think it took me even 30 seconds to find what I was looking for: a pet door that was mostly designed for cats but also works perfectly for the tiny Pekingese dog breed.I wouldn't say this pet door is perfect, but it is well made, with a strong frame and side panels. The door itself is perhaps a little flimsy, but as long as it is not abused, it should last a long time.One feature I did not realize the door offered when I ordered it is a one-way setting. Meaning when you feel that your dog or cat has had enough outside time for the night, you can set the latch all the way to the left, which will allow the door to open inward but not outward.The latching mechanism is a bit of an annoyance in one way, though: the door simply does not settle back into the right position for the latch to do what it needs to do and there is no easy way to get it there, since the door has nothing to grab on to. We arrived at a simple solution for that, though: we attached a 1-inch suction cup to the lower right corner of the door so that we can pull the door inward to the right position for latching. Easy Peasy. Ideal Pet Products would do well to include a suction cup for this reason. Hopefully they read these reviews.The side panels are spring-loaded, so you won't have to hold them in place while you tighten the knobs. Just squeeze the panels inward so that the unit is narrower than the window opening; tighten the knobs; set the unit in place; loosen the knobs; let the side panels settle into the sash; then tighten the knobs again.Amazon will recommend that you buy foam weather stripping. Don't do it; the door comes with some. Now I have some weather stripping that I will likely never use. Will I be initiating a return for a $7 package of weather stripping? Nah. And in fact, I have not yet added the weather stripping that came with it. It just doesn't get cold enough here for me to feel all that motivated to add it. But I will. Eventually.Regarding the width: My window is just about 28" wide and this product was JUST wide enough. So when they say 23"-28", they mean it. Could you rig up some expansion panels from some other material, like plywood or something? Sure. But just be aware that if you buy the 23"-28" version of this product and your window is wider than that, you *will* need to come up with a way to adapt it.You might consider adding some sliding window locks if you live in an area where break-ins are a problem. Obviously, if a thief wants in badly enough, they're going to get in, but deterrence measures may slow them down enough that they either give up or get caught in the process. Many people forget that there are many types of thieves: professional thieves, determined thieves, desperate thieves, and casual thieves. The latter will try a window or door and only enter if that window or door opens easily. A little resistance and they give up. The other three groups are unlikely to be deterred, but if you can reduce risk by 25%, isn't it worth it to spend a few dollars for a little added security? I think so.But back to the dogs. One is a bit of a wild child. She loves to play. She takes risks. She throws her weight around. And she steals treats. She got used to the door over the course of one day. She goes out and comes back in several times per night as if she was raised from birth with pet door opening as her purpose in life. Two weeks later, however, we still have to push the other dog - a prissy, prancing little wuss (unless the wild child steals her treats, in which case it's a Battle Royale) - out the little door because she typically won't go through on her own. And when she's ready to come back in? She looks at us through the transparent door and whines to get us to help her come back in. That being said, she has gone out and come back in a few times on her own. She will get used to it. We went through the same thing when we installed the screen on the door. She is simply slow to adapt. But again, she'll get it. Eventually. It's something you should keep in mind for your own beasts. Work with them. Show them how to use it. If they stare at you from outside, use your willpower and don't let them in. Wait them out. Offer them treats to entice them to come back in on their own. Eventually, if they want in bad enough, they will use the door.Overall, I am happy with my purchase. And at least one of my dogs is also happy with my purchase. The other dog thinks it is a gateway to hell. Maybe she's right.Ok, first off, I was expecting some cheap knock off of a real cat door/window. It arrived in a heavy slender cardboard box, structurally more stiff than most packaging, and it had a convenient carrying handle on the top. When I picked it up, it had some weight to it, so while I knew it was aluminum, I didn't have any expectation of how sturdy it would be and how well constructed.This thing installed, literally, in 35 seconds, once I took it out of the box. It's design allows it to work with the modern windows installed in our very old farmhouse. I set it in the track, lined up the ends, unscrewed the SPRING LOADED expanding sides (a very nice touch), using the thumbscrews and pulled the window down. Period. It was installed. I used duct tape to hold the window down in place, which matches my window color (bought here on Amazon). Since the window is in my home office, where kitty loves to stay all day trampling on my desk and keyboard, I wasn't concerned with the look. But you can see in the pic it doesn't look bad.I'm not good at anything construction-wise, but this product is a blessing. BTW.. It was $140.00 less expensive on Amazon than other pet stores or online stores. AMAZING.One thing I am EXTREMELY happy with is that it is not exactly as shown in the video. The video description shows a plastic door insert to keep your pet from going in and out, that is, to keep the flap from opening and closing. I wouldn't have been able to use that due to the location of the window ledge used to close and open the window. This model has a red knob that can lock it closed and it has a magnetic pull that keeps a breeze from opening the flap. Kitty just has to push a little bit if she wants in and out. I have huge windows sills inside and outside of the window. This window goes to the second floor balcony, her favorite place to watch birds at the feeder and the tree.This pet door was easy to install. The plastic door is fairly firm and takes a small bit of effort to push. I had one cat who learned quickly the trick of getting in and out. I had a second cat, who disliked having to push the door with his head. He could do it but wasn't happy about it. I had to force him to use it for a couple of weeks by refusing to let him in through the people door. Some times we actually gently pushed him through. He did finally learn to use it on his own. He still prefers the people door, but he will go in and out the pet door no problem. And I am happy to know the cats come in when its either too hot or too cold for them, and we are not home to let them enter.The pet door was easy to install, and overall works well, but there are a few things that knock the rating down a bit:1. There is a gap above the flap (see pic) that is open to the outside and I've had small bugs come through. I know I will also feel a cold draft through it in the winter. I'm sure heat is coming in too during the summer but not that noticeable right now.2. Whilst trying to teach my cats to use the door, it was very difficult to pull the flap towards me to encourage them to come back in as there was nothing to pull on. I ended up putting a suction cup with a hook on it to pull it inwards (see pic). It would be nice if there was a small handle to make easier.3. When the cats come back in the flap doesn't always close all the way leaving it open to the outside for heat and bugs to come in the house.4. The instructions showed items to secure the window so it can't be opened from the outside but they weren't included in the box so had to buy something separately.The hardest part about this, and it's not really a fault of the product, is that I could never get the cats to ever use it by themselves to go outside. Two of them eventually figured out how to come back in on their own after they were out for a while, but I always have to put them out there myself. They just won't use the flap to go out without me holding it open for them.This product is amazing. So easy to fit and does exactly what it says. Just wish my cat would use it now but it's early days.Exactly what we needed, we live in a rented apartment and are unable to make a hole in a door for a cat flap - this solves that issue purfectly.Great product fits perfectlyEasy to fit our cat enjoys using it