diff --git a/src/pocketmine/item/Armor.php b/src/pocketmine/item/Armor.php
index 27f442706..340f647be 100644
--- a/src/pocketmine/item/Armor.php
+++ b/src/pocketmine/item/Armor.php
@@ -26,7 +26,7 @@ namespace pocketmine\item;
 
 abstract class Armor extends Item{
 
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 1;
 	}
 }
\ No newline at end of file
diff --git a/src/pocketmine/item/Bed.php b/src/pocketmine/item/Bed.php
index fece690a3..1d6b1487b 100644
--- a/src/pocketmine/item/Bed.php
+++ b/src/pocketmine/item/Bed.php
@@ -32,7 +32,7 @@ class Bed extends Item{
 		parent::__construct(self::BED, $meta, "Bed");
 	}
 
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 1;
 	}
 }
\ No newline at end of file
diff --git a/src/pocketmine/item/BeetrootSoup.php b/src/pocketmine/item/BeetrootSoup.php
index 011846038..041841e03 100644
--- a/src/pocketmine/item/BeetrootSoup.php
+++ b/src/pocketmine/item/BeetrootSoup.php
@@ -29,7 +29,7 @@ class BeetrootSoup extends Food{
 		parent::__construct(self::BEETROOT_SOUP, $meta, "Beetroot Soup");
 	}
 
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 1;
 	}
 
diff --git a/src/pocketmine/item/Bucket.php b/src/pocketmine/item/Bucket.php
index 86c470453..b906575de 100644
--- a/src/pocketmine/item/Bucket.php
+++ b/src/pocketmine/item/Bucket.php
@@ -37,7 +37,7 @@ class Bucket extends Item{
 		parent::__construct(self::BUCKET, $meta, "Bucket");
 	}
 
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 1;
 	}
 
diff --git a/src/pocketmine/item/Cake.php b/src/pocketmine/item/Cake.php
index 4ac6544c1..a8ccc8120 100644
--- a/src/pocketmine/item/Cake.php
+++ b/src/pocketmine/item/Cake.php
@@ -32,7 +32,7 @@ class Cake extends Item{
 		parent::__construct(self::CAKE, $meta, "Cake");
 	}
 
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 1;
 	}
 }
\ No newline at end of file
diff --git a/src/pocketmine/item/IronDoor.php b/src/pocketmine/item/IronDoor.php
index 8fbce996b..518f14c20 100644
--- a/src/pocketmine/item/IronDoor.php
+++ b/src/pocketmine/item/IronDoor.php
@@ -32,7 +32,7 @@ class IronDoor extends Item{
 		parent::__construct(self::IRON_DOOR, $meta, "Iron Door");
 	}
 
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 1;
 	}
 }
\ No newline at end of file
diff --git a/src/pocketmine/item/Item.php b/src/pocketmine/item/Item.php
index c5fca5f9f..dc569b17a 100644
--- a/src/pocketmine/item/Item.php
+++ b/src/pocketmine/item/Item.php
@@ -734,7 +734,7 @@ class Item implements ItemIds, \JsonSerializable{
 	 * Returns the highest amount of this item which will fit into one inventory slot.
 	 * @return int
 	 */
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 64;
 	}
 
diff --git a/src/pocketmine/item/MushroomStew.php b/src/pocketmine/item/MushroomStew.php
index 8a2db5d08..a3776393d 100644
--- a/src/pocketmine/item/MushroomStew.php
+++ b/src/pocketmine/item/MushroomStew.php
@@ -28,7 +28,7 @@ class MushroomStew extends Food{
 		parent::__construct(self::MUSHROOM_STEW, $meta, "Mushroom Stew");
 	}
 
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 1;
 	}
 
diff --git a/src/pocketmine/item/Sign.php b/src/pocketmine/item/Sign.php
index 834be4e9a..b8a6e5c77 100644
--- a/src/pocketmine/item/Sign.php
+++ b/src/pocketmine/item/Sign.php
@@ -32,7 +32,7 @@ class Sign extends Item{
 		parent::__construct(self::SIGN, $meta, "Sign");
 	}
 
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 16;
 	}
 }
\ No newline at end of file
diff --git a/src/pocketmine/item/Snowball.php b/src/pocketmine/item/Snowball.php
index 4a378d947..cd5abcbe4 100644
--- a/src/pocketmine/item/Snowball.php
+++ b/src/pocketmine/item/Snowball.php
@@ -29,7 +29,7 @@ class Snowball extends Item{
 		parent::__construct(self::SNOWBALL, $meta, "Snowball");
 	}
 
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 16;
 	}
 
diff --git a/src/pocketmine/item/Tool.php b/src/pocketmine/item/Tool.php
index b2b612f30..fe6376f1d 100644
--- a/src/pocketmine/item/Tool.php
+++ b/src/pocketmine/item/Tool.php
@@ -40,7 +40,7 @@ abstract class Tool extends Item{
 	const TYPE_AXE = 4;
 	const TYPE_SHEARS = 5;
 
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 1;
 	}
 
diff --git a/src/pocketmine/item/WoodenDoor.php b/src/pocketmine/item/WoodenDoor.php
index 3ea688ad3..4402967ab 100644
--- a/src/pocketmine/item/WoodenDoor.php
+++ b/src/pocketmine/item/WoodenDoor.php
@@ -32,7 +32,7 @@ class WoodenDoor extends Item{
 		parent::__construct(self::WOODEN_DOOR, $meta, "Wooden Door");
 	}
 
-	public function getMaxStackSize(){
+	public function getMaxStackSize() : int{
 		return 1;
 	}
 }
\ No newline at end of file