1Double O ring design, no matter adjust the biggest or smallest size, can ensure the traction O ring at center, another O ring can used to hang pet bag/hanging pendant/dog tag. 2Hook and loop and portable buckle design, not hurt neck and omni-dimensional protection, easy to wear and take off, easy to operate, save time. 3Breathable and comfortable mesh fabric, soft and lightweight, give pet different comfortable somatosensory. 4Made of high quality polyester material, sturdy, durable and long service life. 5Can control the pet to prevent the pet from getting lost when go out walking the dog.