How to use SQLBulkcopy C#

SqlBulkCopy productsCopy = new SqlBulkCopy(SqlConnection connnection);

SqlBulkCopy productsCopy = new SqlBulkCopy(String SqlConnection)
 

SqlBulkCopy productsCopy = new SqlBulkCopy(connstring, SqlBulkCopyOptions.Default); 

private static void ProductsCopy()
        {
            string strConnection =
                @"Server=localhost;Database=Northwind;Trusted_Connection=true";
            // get the source data
            using (SqlConnection srcConnection = new SqlConnection(strConnection))
            {
                SqlCommand srcCommand = new SqlCommand("SELECT * FROM Products");
                srcCommand.Connection = srcConnection;  
                srcConnection.Open();
                SqlDataReader reader = srcCommand.ExecuteReader();

                // open the destination data
                using (SqlConnection destConnection = new SqlConnection(strConnection))
                {
                    // open the connection
                    destConnection.Open();

                    using (SqlBulkCopy bulkCopy = new SqlBulkCopy(destConnection.ConnectionString))
                    {
                        bulkCopy.BatchSize = 500;                        
                        bulkCopy.DestinationTableName = "Products_New";
                        bulkCopy.WriteToServer(reader);
                    }
                }

                reader.Close();
            }
        }