I wasn't really sure what to expect when I tried using this with my dog for the first time. The main reason I wanted to try it out is because my dog sometimes wants to stand up in the car and if I have to hit my breaks harder than usual, she's been thrown forward into the floorboard. She doesn't always like to obey the "sit" command when we're in the car. I don't know if she's nervous (doesn't seem like it) or if she's just trying to check out what all is going on around her, but I needed something to keep her from possibly getting injured.The only problem with this is that it pretty much has to be used in the backseat. My dog sometimes likes to sit in the front seat next to me, which I don't mind, but when I hooked her up to the seat belt, she changed her mind and tried to go in the back. Since the belt is long enough, she was able to put her front paws in the back and got herself in a bit of a pickle. However, when she's hooked up to the seat belt in the back of the car, she can't even try to come in the front. So, this kept her from moving from the front to the back during the drive, which she would sometimes do. And when she stood up, it kept her from being slung around and helped keep her feet more steady. So I don't have to worry about her being injured or getting thrown into the back seat or the dashboard or the floorboard. It is also long enough that she can sit, stand, or lay down comfortably. And the hook swivels to match where she is going so she doesn't get tangled. Of course, DO NOT connect this to your dog's collar. It will choke them - it must be connected to a harness. Also, the seatbelt it adjustable so you can control how much space you want your dog to have. If you have a medium-sized or large dog, I recommend keeping it at the longest length possible, because it's probably the most comfortable. My dog wasn't so sure about the seatbelt at first, but after a while she started acting normal and took a nap or stood up to look around.