A Cover Letter to your CV ought to carry soul of your CV. It is a short teaser, that excites the reader about your profile. In fact, it can be a piece of art, that beautifully, and using the full force of narrational English, showcases your background, skills and motivation in applying for the next job. It can engage the recruiter better than any formatted CV attempts to. Can be used as the email advancing your CV. The subject line suggested for the email also carries punch. Your identity shines through, and attention can be solicited on high points of your profile.