diff --git a/.gitignore b/.gitignore
index d4e756478..50ef963d5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,3 +26,4 @@ gradle.properties
 
 # Other
 *~
+.nb-gradle-properties
diff --git a/api b/api
index 87b3cd16c..960034e1e 160000
--- a/api
+++ b/api
@@ -1 +1 @@
-Subproject commit 87b3cd16caccfb9a0f9f1d793d93b69ef6c1ec95
+Subproject commit 960034e1e62ba1e89f1c293cbb8240f22cc28f3b
diff --git a/src/main/java/forestry/storage/BackpackDefinition.java b/src/main/java/forestry/storage/BackpackDefinition.java
index 20a89e307..e55dfe6a6 100755
--- a/src/main/java/forestry/storage/BackpackDefinition.java
+++ b/src/main/java/forestry/storage/BackpackDefinition.java
@@ -20,6 +20,7 @@ import forestry.core.config.Defaults;
 import forestry.core.utils.StringUtil;
 
 public class BackpackDefinition implements IBackpackDefinition {
+
 	final String name;
 
 	final int primaryColor; // - c03384
@@ -64,12 +65,10 @@ public class BackpackDefinition implements IBackpackDefinition {
 
 	@Override
 	public void addValidItem(ItemStack validItem) {
-		if (validItem.getItem() != null) {
+		if (validItem.getItem() != null)
 			this.validItems.add(validItem);
-		}
 	}
 
-	@Override
 	public ArrayList<ItemStack> getValidItems(EntityPlayer player) {
 		return validItems;
 	}
@@ -77,13 +76,12 @@ public class BackpackDefinition implements IBackpackDefinition {
 	@Override
 	public boolean isValidItem(EntityPlayer player, ItemStack itemstack) {
 		for (ItemStack stack : getValidItems(player))
-			if (stack != null && stack.getItem() != null ) {
+			if (stack != null && stack.getItem() != null)
 				if (stack.getItemDamage() == Defaults.WILDCARD) {
 					if (stack.getItem() == itemstack.getItem())
 						return true;
 				} else if (stack.isItemEqual(itemstack))
 					return true;
-			}
 
 		return false;
 	}
diff --git a/src/main/java/forestry/storage/gui/ContainerBackpack.java b/src/main/java/forestry/storage/gui/ContainerBackpack.java
index 783bbece1..63d4ce780 100755
--- a/src/main/java/forestry/storage/gui/ContainerBackpack.java
+++ b/src/main/java/forestry/storage/gui/ContainerBackpack.java
@@ -4,7 +4,7 @@
  * are made available under the terms of the GNU Lesser Public License v3
  * which accompanies this distribution, and is available at
  * http://www.gnu.org/licenses/lgpl-3.0.txt
- * 
+ *
  * Various Contributors including, but not limited to:
  * SirSengir (original work), CovertJaguar, Player, Binnie, MysteriousAges
  ******************************************************************************/
@@ -15,13 +15,13 @@ import net.minecraft.item.ItemStack;
 
 import forestry.core.config.Defaults;
 import forestry.core.gui.ContainerItemInventory;
-import forestry.core.gui.slots.SlotCustom;
+import forestry.core.gui.slots.SlotForestry;
 import forestry.core.utils.ItemInventory;
 import forestry.storage.items.ItemBackpack;
 
 public class ContainerBackpack extends ContainerItemInventory {
 
-	public ContainerBackpack(EntityPlayer player, ItemInventory inventory) {
+	public ContainerBackpack(final EntityPlayer player, ItemInventory inventory) {
 		super(inventory, player);
 
 		int lines = 0;
@@ -44,7 +44,14 @@ public class ContainerBackpack extends ContainerItemInventory {
 		for (int j = 0; j < lines; j++)
 			for (int k = 0; k < columns; k++) {
 				int slot = k + j * columns;
-				addSlot(new SlotCustom(inventory, ((ItemBackpack) inventory.parent.getItem()).getValidItems(player), slot, startX + k * 18, startY + j * 18));
+				addSlot(new SlotForestry(inventory, slot, startX + k * 18, startY + j * 18) {
+
+					@Override
+					public boolean isItemValid(ItemStack stack) {
+						return isAcceptedItem(player, stack);
+					}
+
+				});
 			}
 
 		// Player inventory
diff --git a/src/main/java/forestry/storage/items/ItemBackpack.java b/src/main/java/forestry/storage/items/ItemBackpack.java
index a7a2fae01..ae7b6bf57 100755
--- a/src/main/java/forestry/storage/items/ItemBackpack.java
+++ b/src/main/java/forestry/storage/items/ItemBackpack.java
@@ -10,7 +10,6 @@
  ******************************************************************************/
 package forestry.storage.items;
 
-import java.util.Collection;
 import java.util.List;
 import java.util.Locale;
 
@@ -190,7 +189,7 @@ public class ItemBackpack extends ItemInventoried {
 			if (targetStack == null)
 				continue;
 
-			if(!info.isValidItem(player, targetStack))
+			if (!info.isValidItem(player, targetStack))
 				continue;
 
 			ItemStack remaining = InvTools.moveItemStack(targetStack, backpackInventory);
@@ -215,15 +214,11 @@ public class ItemBackpack extends ItemInventoried {
 		return stack.getItem() == this;
 	}
 
-	public Collection<ItemStack> getValidItems(EntityPlayer player) {
-		return info.getValidItems(player);
-	}
-
 	public int getBackpackSize() {
 		return getSlotsForType(type);
 	}
 
-	@SuppressWarnings({ "rawtypes", "unchecked" })
+	@SuppressWarnings({"rawtypes", "unchecked"})
 	@Override
 	public void addInformation(ItemStack itemstack, EntityPlayer player, List list, boolean flag) {
 		ItemInventory inventory = new ItemInventory(ItemBackpack.class, getBackpackSize(), itemstack);
diff --git a/src/main/java/forestry/storage/items/ItemNaturalistBackpack.java b/src/main/java/forestry/storage/items/ItemNaturalistBackpack.java
index 27c794d99..194e8f254 100755
--- a/src/main/java/forestry/storage/items/ItemNaturalistBackpack.java
+++ b/src/main/java/forestry/storage/items/ItemNaturalistBackpack.java
@@ -4,14 +4,12 @@
  * are made available under the terms of the GNU Lesser Public License v3
  * which accompanies this distribution, and is available at
  * http://www.gnu.org/licenses/lgpl-3.0.txt
- * 
+ *
  * Various Contributors including, but not limited to:
  * SirSengir (original work), CovertJaguar, Player, Binnie, MysteriousAges
  ******************************************************************************/
 package forestry.storage.items;
 
-import java.util.ArrayList;
-
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.item.ItemStack;
 
@@ -56,9 +54,4 @@ public class ItemNaturalistBackpack extends ItemBackpack {
 	public void openGui(EntityPlayer player, ItemStack itemstack) {
 		player.openGui(ForestryAPI.instance, guiId, player.worldObj, (int) player.posX, (int) player.posY, (int) player.posZ);
 	}
-
-	@Override
-	public ArrayList<ItemStack> getValidItems(EntityPlayer player) {
-		return null;
-	}
 }