This is harness and leash set specially designed for cats, which can effectively prevent cats from escaping when they walk out.Professionally used for walking, running, etc., to make going out safer. The Size chart you can refer : SMALL SIZE neck girth:7"-11", chest girth:10.5"-16" ; MEDIUM SIZE neck girth:11"-14.3", chest girth:16"-20".Please measure the size of your pet before buying and choose the correct size for purchase. Escape Proof Cat Harness 🐱 This cat harness has a safety buckle on the neck and chest. The buckle can be quickly closed and firmly fixed and manual operation to open it, which are very convenient for putting on and taking off, and double security to prevent cats from escaping. In addition, this cat harness adds a 360-degree reflective design, which works perfectly in dim environments, making it safer for cats to walk at night. Comfortable to Wear 🐱 This cat harness is made of mesh fabric, which is soft and breathable, suitable for all seasons. There is no sense of restraint when wearing pets. At the same time, the wide-range adjustable design is our ingenuity. We have improved the limited adjustment of the ordinary cat harness and replaced it with a 360 degree adjustable nylon strap, which can achieve the maximum adjustment and the minimum adjustment within a certain range, so cats will wear more comfortably.