string builder for concatinating strings

StringBuilder sb = new StringBuilder();
sb.AppendFormat("{0}-{1}-{2}-{3}-{4}",
   this.RBLstSeries.SelectedValue.ToString(),
   this.RBLstDamper.SelectedValue.Substring(0, 3).ToString(),
   this.RBLstStyle.SelectedValue.Substring(0, 1).ToString(),
   this.RBLstFrontLipDesign.SelectedValue.Substring(0, 1).ToString(),
   this.RBLstApronDesign.SelectedValue.Substring(0, 1).ToString());
this.TxtHdModelNo.Text = sb.ToString();