The claims of an invention (utility model) comprise a concise verbal characteristic of the technical essence of the invention (utility model) incorporating a totality of its essential features which are sufficient for obtaining the claimed technical achievement. Once a patent is granted, it is the claims that assume a legal nature and become the sole criterion  for determining the scope of the invention (it is used to decide whether the invention has been exploited or not).
The claims must be supported by the description, that is, the invention (utility model) should be described in the claims in terms of the same concepts as in the description. 
The features of an invention (utility model) must be represented in the claims in such a manner that enables their identification, that is, they must be described in terms and concepts having a uniform, unequivocal meaning and scope for a person skilled in the art.
An invention (utility model) may be characterized in one or more claims.