The Comfy Cone Extender Panel is specially made to extend the length of the X-Large Comfy Cone Collar for Dogs & Cats or Medium-Extra Long Comfy Cone Collar for Dogs & Cats.
If between sizes like my girl was this is perfect. The Velcro makes removal and putting on very easy
The extender is ok. But I found that each time my dog passed thru the door or caught on anything it would pull apart pretty easily. And it made the cone rather bulky. I think if I had to do it over again I would just buy the bigger size.