Game Changer!Bought 36” size for our 70 lb German Shepherd/+10 mix (in photo). For purebred lab or GS, I would suggest the 42” size (Our dog has shorter legs and nose). If using in your vehicle, measure opening before ordering. The 36” fits partially expanded into the backseat of our Forester. THEN, I easily connect the bottom frame bars and top frame bars. (Watch fingers so not to pinch). Simple to assemble. The crate sits wider (25”) than the seat so I use pillows on the back floor to level the empty space up to the front seats, in case I were to slam on the brakes. You can also buy on Amazon or create a flat surface up to the front seats, but I thought about airbag safety. Besides, the pillows work just fine and my dog doesn’t move around much. He settles right in and relaxes, instead of always being on high alert as before. I leave our crate in the car. You can place your groceries or other items in it when dog is not occupying it. NO, this would not be good for leaving dogs alone who have separation anxiety and destroy things. It is soft sided and has mesh. With our rescue dog, it is all about fear of the outside world. After a year of good behavior while on car rides, he started reacting very aggressively whenever passing any human or wildlife. No explanation, never left in the car alone. Our 10 minute drive to trails became very stressful, trying our best to distract his attention from sights and sounds with treats, keeping the windows up. I like that one side is solid, so I face that to the curb side. We pass people or animals, no problem. Love the side compartment and zippered mesh openings for treat giving. Now, it is an enjoyable ride for all of us!Ordering a second one for him to use indoors whenever he wants. A space saver compared to the huge metal crate stored in the garage.