This is perfect for peace of mind. I needed something we could use easily in a sedan with some crash-testing and the safety videos really gave me confidence in the product. The size small fits my 40 lb border collie / heeler puppy. She can lay down, sit up, and look around without any issue. It adds 3-4 minutes to getting in and out of the car to put her in this, snap in, and then change into her walking or hiking harness. It can be annoying sometimes but it's well worth the safety if you don't have room in your car for a crash-tested kennel.