Pls clarify the following 'param1'

public void GetPositionName(string PosCode)
{
    if (cn.State == ConnectionState.Open)
    {
        cn.Close();
    }
    cn.Open();
    lblConnectionState.Text = "CONNECTED";

    cmd.Connection = cn;
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.CommandText = "GET_POSITION_NAME";

    SqlParameter param1 = new SqlParameter();
    param1.ParameterName = "POSITION_CODE";
    param1.Direction = ParameterDirection.Input;
    param1.SqlDbType = SqlDbType.VarChar;
    param1.Value = PosCode;
    param1.Value = Session["selected_position_code"];

    cmd.Parameters.Add(param1);

    da.SelectCommand = cmd;
    da.Fill(ds);

    DataTable dt =  ds.Tables[0];
    lblPositionName.Text = dt.Rows[0]["POSITION_NAME"].ToString();

}