Tips: Please make sure your pet fits the cart before purchase. In addition, you could consider putting a mat or blanket in the cart, providing a more comfortable experience for your pet. Extra Long & Extendable Rear: The 17.3" extended rear has three gears for adjustment. You can choose the right gear according to your needs. Putting the rear down directly can be used as a pet climbing. At the same time, anti-skid design is made on the climbing surface and bottom.