This setting allows for fractional rating, four options are available:
Item – Undivided stars, you will only be allowed to select whole stars. Each star represents a whole number. Example 4 our of 5.
Half – Each star is divided into two. For example, this would allow 1.5 or 3.5 star rating.
Exact – Each star is divided into a hundred segments. The precision is down to a pixel.
Custom – Allows for a Custom Precision. A star can be divided into as many as a hundred segments.