diff --git a/src/material/block/solid/BurningFurnace.php b/src/material/block/solid/BurningFurnace.php
index cc663b1d4..b1c3c19b4 100644
--- a/src/material/block/solid/BurningFurnace.php
+++ b/src/material/block/solid/BurningFurnace.php
@@ -98,7 +98,7 @@ class BurningFurnaceBlock extends SolidBlock{
 			"slots" => 3,
 			"title" => "Furnace",
 		));
-		for($s = 0; $s < 3; ++$s){
+		for($s = 0; $s < FURNACE_SLOTS; ++$s){
 			$slot = $furnace->getSlot($s);
 			if($slot->getID() > 0 and $slot->count > 0){
 				$player->dataPacket(MC_CONTAINER_SET_SLOT, array(
diff --git a/src/material/block/solid/Chest.php b/src/material/block/solid/Chest.php
index 1f3de6fe2..d774db2b9 100644
--- a/src/material/block/solid/Chest.php
+++ b/src/material/block/solid/Chest.php
@@ -110,7 +110,7 @@ class ChestBlock extends SolidBlock{
 			"slots" => 27,
 			"title" => "Chest",
 		));
-		for($s = 0; $s < 3; ++$s){
+		for($s = 0; $s < CHEST_SLOTS; ++$s){
 			$slot = $chest->getSlot($s);
 			if($slot->getID() > 0 and $slot->count > 0){
 				$player->dataPacket(MC_CONTAINER_SET_SLOT, array(