diff --git a/include/class-MailboxAPI.php b/include/class-MailboxAPI.php
index bad385a..e06fa8c 100644
--- a/include/class-MailboxAPI.php
+++ b/include/class-MailboxAPI.php
@@ -1,118 +1,132 @@
 <?php
-# Copyright (C) 2018, 2019 Valerio Bozzolan
+# Copyright (C) 2018, 2019, 2020 Valerio Bozzolan
 # Boz Libre Hosting Panel
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as
 # published by the Free Software Foundation, either version 3 of the
 # License, or (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 // load dependend traits
 class_exists( 'DomainAPI' );
 
 /**
  * Methods for a MailboxAPI class
  */
 trait MailboxAPITrait {
 
 	use DomainAPITrait;
 
 	/**
 	 * Limit to a specific mailbox
 	 *
 	 * @param  object $mailbox Mailbox
 	 * @return self
 	 */
 	public function whereMailbox( $mailbox ) {
-		return $this->whereDomain( $mailbox )
-		            ->whereMailboxUsername( $mailbox->getMailboxUsername() );
+		return $this->whereMailboxID( $mailbox->getMailboxID() );
+	}
+
+	/**
+	 * Limit to a specific Mailbox ID
+	 *
+	 * @param  int  $id Mailbox ID
+	 * @return self
+	 */
+	public function whereMailboxID( $id ) {
+		return $this->whereInt( $this->MAILBOX_ID, $id );
 	}
 
 	/**
 	 * Filter a specific Mailbox username
 	 *
 	 * @param  string $username Mailbox username (without domain name)
 	 * @return self
 	 */
 	public function whereMailboxUsername( $username ) {
 		return $this->whereStr( 'mailbox_username', $username );
 	}
 
 	/**
 	 * Where the Mailbox is Active (or not)
 	 *
 	 * @param  boolean $active If you want the active, or the inactive
 	 * @return self
 	 */
 	public function whereMailboxIsActive( $active = true ) {
 		return $this->whereInt( 'mailbox_active', $active );
 	}
 
 	/**
 	 * Join mailboxes and domain (once)
 	 *
 	 * @return self
 	 */
 	public function joinMailboxDomain() {
 		if( empty( $this->joinedMailboxDomain ) ) {
 			$this->from( 'domain' );
 			$this->equals( 'domain.domain_ID', 'mailbox.domain_ID' );
 
 			$this->joinedMailboxDomain = true;
 		}
 		return $this;
 	}
 
 	/**
 	 * Check if I can edit this mailbox
 	 *
 	 * Actually it just checks if you can edit the whole domain.
 	 *
 	 * @return boolean
 	 */
 	public function whereMailboxIsEditable() {
 		return $this->whereDomainIsEditable();
 	}
 
 }
 
 /**
  * Mailbox API
  */
 class MailboxAPI extends Query {
 
 	use MailboxAPITrait;
 
 	/**
 	 * Univoque Domain ID column name
 	 *
 	 * Used by DomainAPITrait
 	 */
 	const DOMAIN_ID = 'mailbox.domain_ID';
 
 	/**
 	 * Univoque Plan ID column name
 	 */
-	const PLAN_ID = 'domain.plan_ID';
+	protected $PLAN_ID = 'domain.plan_ID';
+
+	/**
+	 * Univoque column name to the Mailbox ID
+	 */
+	protected $MAILBOX_ID = 'mailbox.mailbox_ID';
 
 	/**
 	 * Constructor
 	 */
 	public function __construct( $db = null ) {
 
 		// set database and class name
 		parent::__construct( $db, Mailbox::class );
 
 		// set database table
 		$this->from( Mailbox::T );
 	}
 
 }
diff --git a/include/class-MailboxQuota.php b/include/class-MailboxQuota.php
index b49529f..3606efe 100644
--- a/include/class-MailboxQuota.php
+++ b/include/class-MailboxQuota.php
@@ -1,81 +1,83 @@
 <?php
 # Copyright (C) 2018, 2019 Valerio Bozzolan
 # Boz Libre Hosting Panel
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as
 # published by the Free Software Foundation, either version 3 of the
 # License, or (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 // load dependent traits
 class_exists( 'Mailbox' );
 
 /**
  * Methods for a MailboxQuota class
  */
 trait MailboxQuotaTrait {
 
 	/**
 	 * Get the Mailbox quota date
 	 *
 	 * @return DateTime
 	 */
 	public function getMailboxQuotaDate() {
 		return $this->get( 'mailboxquota_date' );
 	}
 
 	/**
 	 * Get the Mailbox quota bytes
 	 *
 	 * @return int
 	 */
 	public function getMailboxQuotaBytes() {
 		return $this->get( 'mailboxquota_bytes' );
 	}
 
 	/**
 	 * Get the Mailbox quota size readable for humans
 	 *
 	 * @return string
 	 */
 	public function getMailboxQuotaHumanSize() {
 		$size = $this->getMailboxQuotaBytes();
 		return human_filesize( $size );
 	}
 
 	/**
 	 * Normalize a MailboxQuota object after being retrieved from database
 	 */
-	protected static function normalizeMailboxQuota() {
+	protected function normalizeMailboxQuota() {
 		$this->integers(  'mailboxquota_bytes' );
 		$this->datetimes( 'mailboxquota_date' );
 	}
 
 }
 
 /**
  * Rappresentation of a Mailbox quota size
  */
 class MailboxQuota extends Queried {
 
+	use MailboxQuotaTrait;
+
 	/**
 	 * Table name
 	 */
 	const T = 'mailboxquota';
 
 	/**
 	 * Constructor
 	 */
 	public function __construct() {
 		$this->normalizeMailboxQuota();
 	}
 
 }
diff --git a/include/class-MailboxQuotaAPI.php b/include/class-MailboxQuotaAPI.php
index 966fadd..e04e7f9 100644
--- a/include/class-MailboxQuotaAPI.php
+++ b/include/class-MailboxQuotaAPI.php
@@ -1,118 +1,54 @@
 <?php
-# Copyright (C) 2018, 2019 Valerio Bozzolan
-# Boz Libre Hosting Panel
+# Copyright (C) 2018, 2019, 2020 Valerio Bozzolan
+# KISS Libre Hosting Panel
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as
 # published by the Free Software Foundation, either version 3 of the
 # License, or (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 // load dependend traits
 class_exists( 'MailboxAPI' );
 
 /**
  * Methods for a MailboxQuotaAPI class
  */
 trait MailboxQuotaAPITrait {
 
 	use MailboxAPITrait;
 
-	/**
-	 * Limit to a specific mailbox
-	 *
-	 * @param  object $mailbox MailboxQuota
-	 * @return self
-	 */
-	public function whereMailboxQuota( $mailbox ) {
-		return $this->whereDomain( $mailbox )
-		            ->whereMaiboxUsername( $mailbox->getMailboxQuotaUsername() );
-	}
-
-	/**
-	 * Filter a specific MailboxQuota username
-	 *
-	 * @param  string $username MailboxQuota username (without domain name)
-	 * @return self
-	 */
-	public function whereMailboxQuotaUsername( $username ) {
-		return $this->whereStr( 'mailbox_username', $username );
-	}
-
-	/**
-	 * Where the MailboxQuota is Active (or not)
-	 *
-	 * @param  boolean $active If you want the active, or the inactive
-	 * @return self
-	 */
-	public function whereMailboxQuotaIsActive( $active = true ) {
-		return $this->whereInt( 'mailbox_active', $active );
-	}
-
-	/**
-	 * Join mailboxes and domain (once)
-	 *
-	 * @return self
-	 */
-	public function joinMailboxQuotaDomain() {
-		if( empty( $this->joinedMailboxQuotaDomain ) ) {
-			$this->from( 'domain' );
-			$this->equals( 'domain.domain_ID', 'mailbox.domain_ID' );
-
-			$this->joinedMailboxQuotaDomain = true;
-		}
-		return $this;
-	}
-
-	/**
-	 * Check if I can edit this mailbox
-	 *
-	 * Actually it just checks if you can edit the whole domain.
-	 *
-	 * @return boolean
-	 */
-	public function whereMailboxQuotaIsEditable() {
-		return $this->whereDomainIsEditable();
-	}
-
 }
 
 /**
  * MailboxQuota API
  */
 class MailboxQuotaAPI extends Query {
 
 	use MailboxQuotaAPITrait;
 
 	/**
-	 * Univoque Domain ID column name
-	 *
-	 * Used by DomainAPITrait
-	 */
-	const DOMAIN_ID = 'mailbox.domain_ID';
-
-	/**
-	 * Univoque Plan ID column name
+	 * Univoque column name to the Mailbox ID
 	 */
-	const PLAN_ID = 'domain.plan_ID';
+	protected $MAILBOX_ID = 'mailboxquota.mailbox_ID';
 
 	/**
 	 * Constructor
 	 */
 	public function __construct( $db = null ) {
 
 		// set database and class name
 		parent::__construct( $db, MailboxQuota::class );
 
 		// set database table
 		$this->from( MailboxQuota::T );
 	}
 
 }