To ensure A proper FIT, please measure the neck circumference of your FURBABYS Neck.Our banadana fits necks up to:XSMALL: 12" NeckSMALL: 14" NeckMEDIUM: 16" NeckLARGE: 20" NeckXLARGE: 24" NeckIf in doubt, always size up! If you need a different size than what we have available, please contact us and let us know. If you know your fur baby's neck measurement and they are in between sizes please contact me and I can adjust the buttons to suit.