wp_mail(
            apply_filters( 'woocommerce_email_recipient_no_stock', get_option( 'woocommerce_stock_email_recipient' ), $product, null ),
            apply_filters( 'woocommerce_email_subject_no_stock', $subject, $product, null ),
            apply_filters( 'woocommerce_email_content_no_stock', $message, $product ),
            apply_filters( 'woocommerce_email_headers', '', 'no_stock', $product, null ),