1. Back Length: Measuring from neck to tail root, keep 2-3cm for total length. Chest Circumference: Measuring the logest chest perimeter, keep 2-3cm for total length. Neck Circumference: Measuring the length around the neck, keep 2-3cm for total length. 2. The Sweater is made by Chenille.The main feature of chenille fabric is the fiber. Once the fiber is held together with the core yarn, the suede will appear fuller, with a velvet texture, soft and comfortable to the touch, without the feeling of piercing. Soft touch, high-end atmosphere, good water absorption, and good drape . The disadvantage is that the elasticity is very small , so you need to buy a larger size when you buy it. Note: All these size recommendations are only applicable to hairless cats. The XS size is suitable for new born baby weighing 1-2 pounds (approximately 0.5-1 kg).suit for bellow 2 months. The S size is suitable for babies weighing 2-3 pounds (approximately 1-1.5 kg). Suit for 3-4 months. The M size is suitable for babies weighing 4-5.5 pounds (approximately 2-2.7 kg). suit for 5-6 months. Size L is suitable for 5.5-7 pounds (approximately 2.7-3.5 kg). suit for 7-8 months. The XL size fits 7 – 9 pounds (approximately 3.5-4.5 kg). suit for 9-11 months. The XXL size fits 10-12 pounds (approximately 5.0-6 kg). suit for Adult. If your cat is not hairless, but like our shirt, please order one size larger. For more size information, please refer to the size chart below. If the side your purchase is not suitable for your cat, please tell us, we are willing to change for you freely. Princess Pink flying Sleeve Pingapple Navy Classic Sling STYLE Princess Pink flying Sleeve Pingapple Navy Classic Sling