Bird E-Collars are great for stopping feather picking, scratching, biting, and other self-inflicted wounds. Padded neck; adjustable collar. Size Chart Item # Neck Circumference Diameter TK05610 FITS 2-2.75" 6" TK05615 FITS 2.75-3.5" 6" TK05620 FITS 3.25-3.5" 8" TK05625 FITS 3.5-4" 8" TK05630 FITS 3.5-4" 10" TK05635 FITS 4.75-5.5" 10" TK05640 FITS 4.75-5.5" 12" TK05645 FITS 6.25-7.5" 12"