When we analyse codes of avazak.ir web site, we determine that meta description section character number is 160 character. Search engines see the writing which you write on your web site's meta description section , as explanation of your web site. Thus You should write sentence or sentences about your internet site's content to this section. Because search engines read almost till 150 characters, the sentence which you wrote, will be seen as half and It will be seen incomplete on search engine result lists. Thus, we advice you should decrease character number on your meta description code and you should use sensible sentences.