diff --git a/lib/Cron/CronHelper.php b/lib/Cron/CronHelper.php
index a45785aea1..9118d54dbd 100644
--- a/lib/Cron/CronHelper.php
+++ b/lib/Cron/CronHelper.php
@@ -9,9 +9,9 @@ use MailPoet\Util\Security;
 if(!defined('ABSPATH')) exit;
 
 class CronHelper {
-  const DAEMON_EXECUTION_LIMIT = 20;
-  const DAEMON_EXECUTION_TIMEOUT = 35;
-  const DAEMON_REQUEST_TIMEOUT = 2;
+  const DAEMON_EXECUTION_LIMIT = 20; // seconds
+  const DAEMON_EXECUTION_TIMEOUT = 35; // seconds
+  const DAEMON_REQUEST_TIMEOUT = 2; // seconds
   const DAEMON_SETTING = 'cron_daemon';
 
   static function createDaemon($token) {
diff --git a/lib/Cron/Daemon.php b/lib/Cron/Daemon.php
index fa1b11e1a0..d8e13389cb 100644
--- a/lib/Cron/Daemon.php
+++ b/lib/Cron/Daemon.php
@@ -10,7 +10,7 @@ class Daemon {
   public $daemon;
   public $request_data;
   public $timer;
-  const REQUEST_TIMEOUT = 5;
+  const REQUEST_TIMEOUT = 5; // seconds
 
   function __construct($request_data = false) {
     $this->request_data = $request_data;