This is a handmade Elizabethan collar that does not use a plastic core. I have a nursing cat at home, and after making this Elizabethan collar, she bit her hand less during treatment at the hospital. The nursing assistant said, "This is good! It will sell!" so I decided to list it. It does not use plastic, and the core is made of non-woven fabric, making it soft. It is sewn securely, so it is less likely to lose its shape and can be washed, allowing you to keep it clean. Please refer to the photos for the sizes. It has two-stage buttons for fine adjustments. Although it takes a little time, I can also accommodate custom size orders, so please feel free to contact me.