Bandanas for most size pets. There is a sleeve to allow a pet collar to securely hold the bandana in place. You won't have to worry about tying the bandana or losing the bandana during a walk.
Size dimensions are rough estimates:
Small: 9 inches across and 4.5 inches in height
Medium: 12 inches across and 6 inches in height
Large: 18 inches across and 9 inches in height