diff --git a/pom.xml b/pom.xml
index 46c8ba3..49554d6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -8,7 +8,7 @@
     <artifactId>ultrabackpacks-api</artifactId>
     <name>UltraBackpacks API</name>
     <packaging>jar</packaging>
-    <version>1.1.3</version>
+    <version>1.2.0</version>
 
     <build>
         <finalName>UltraBackpacksAPI-${project.version}</finalName>
diff --git a/src/main/java/dev/drawethree/ultrabackpacks/api/UltraBackpacksAPI.java b/src/main/java/dev/drawethree/ultrabackpacks/api/UltraBackpacksAPI.java
index 1756d3b..ab98561 100644
--- a/src/main/java/dev/drawethree/ultrabackpacks/api/UltraBackpacksAPI.java
+++ b/src/main/java/dev/drawethree/ultrabackpacks/api/UltraBackpacksAPI.java
@@ -1,5 +1,6 @@
 package dev.drawethree.ultrabackpacks.api;
 
+import dev.drawethree.ultrabackpacks.api.exception.BackpackNotFoundException;
 import dev.drawethree.ultrabackpacks.api.model.backpack.IBackpackData;
 import dev.drawethree.ultrabackpacks.api.service.BackendAPI;
 import org.bukkit.block.Block;
@@ -7,7 +8,7 @@
 
 import java.util.List;
 
-public class UltraBackpacksAPI {
+public final class UltraBackpacksAPI {
 
 	private UltraBackpacksAPI() {
 		throw new UnsupportedOperationException("Cannot instantiate UltraBackpacksAPI!");
@@ -29,7 +30,7 @@ public static boolean hasBackpack(Player player) {
 	 * @param player Player
 	 * @return BackpackData.class
 	 */
-	public static IBackpackData getBackpackData(Player player) {
+	public static IBackpackData getBackpackData(Player player) throws BackpackNotFoundException {
 		return BackendAPI.getImplementation().getBackpackData(player);
 	}
 
@@ -39,7 +40,7 @@ public static IBackpackData getBackpackData(Player player) {
 	 * @param player  Player
 	 * @param sellAll If true, sells whole backpack. If false, sells only x amount of items based on AutoSell backpack enchant.
 	 */
-	public static void sellBackpack(Player player, boolean sellAll) {
+	public static void sellBackpack(Player player, boolean sellAll) throws BackpackNotFoundException {
 		BackendAPI.getImplementation().sellBackpack(player, sellAll);
 	}
 
diff --git a/src/main/java/dev/drawethree/ultrabackpacks/api/event/BackpackSellEvent.java b/src/main/java/dev/drawethree/ultrabackpacks/api/event/BackpackSellEvent.java
index 2c14977..472dadc 100644
--- a/src/main/java/dev/drawethree/ultrabackpacks/api/event/BackpackSellEvent.java
+++ b/src/main/java/dev/drawethree/ultrabackpacks/api/event/BackpackSellEvent.java
@@ -4,7 +4,7 @@
 import org.bukkit.event.Event;
 import org.bukkit.event.HandlerList;
 
-public class BackpackSellEvent extends Event {
+public final class BackpackSellEvent extends Event {
 
 	private static final HandlerList handlers = new HandlerList();
 
diff --git a/src/main/java/dev/drawethree/ultrabackpacks/api/exception/BackpackNotFoundException.java b/src/main/java/dev/drawethree/ultrabackpacks/api/exception/BackpackNotFoundException.java
new file mode 100644
index 0000000..e3e9895
--- /dev/null
+++ b/src/main/java/dev/drawethree/ultrabackpacks/api/exception/BackpackNotFoundException.java
@@ -0,0 +1,10 @@
+package dev.drawethree.ultrabackpacks.api.exception;
+
+import org.bukkit.entity.Player;
+
+public final class BackpackNotFoundException extends Throwable {
+
+	public BackpackNotFoundException(Player player) {
+		super("Player " + player.getName() + " does not have backpack.");
+	}
+}
diff --git a/src/main/java/dev/drawethree/ultrabackpacks/api/model/backpack/BackpackEnchantment.java b/src/main/java/dev/drawethree/ultrabackpacks/api/model/backpack/BackpackEnchantment.java
new file mode 100644
index 0000000..135a509
--- /dev/null
+++ b/src/main/java/dev/drawethree/ultrabackpacks/api/model/backpack/BackpackEnchantment.java
@@ -0,0 +1,7 @@
+package dev.drawethree.ultrabackpacks.api.model.backpack;
+
+public enum BackpackEnchantment {
+	SELL_MULTI,
+	CAPACITY,
+	AUTO_SELL
+}
diff --git a/src/main/java/dev/drawethree/ultrabackpacks/api/model/backpack/IBackpackData.java b/src/main/java/dev/drawethree/ultrabackpacks/api/model/backpack/IBackpackData.java
index a1a6a11..7e9db6b 100644
--- a/src/main/java/dev/drawethree/ultrabackpacks/api/model/backpack/IBackpackData.java
+++ b/src/main/java/dev/drawethree/ultrabackpacks/api/model/backpack/IBackpackData.java
@@ -1,21 +1,45 @@
 package dev.drawethree.ultrabackpacks.api.model.backpack;
 
-import java.util.Map;
+import org.bukkit.Material;
+import org.bukkit.inventory.ItemStack;
+
+import java.util.List;
 
 public interface IBackpackData {
 
 	/**
-	 * Returns Map of enchants that player has in his backpack.
-	 * Key - Id of enchant
-	 * Value - Level of enchant
-	 * @return Map of enchants belonging to player
+	 * Returns List of backpack items {@link IBackpackItem}
+	 *
+	 * @return list of item in backpack
+	 */
+	List<? extends IBackpackItem> getItems();
+
+	/**
+	 * Adds an item to backpack. If item with type already exists, it adds the quantity to already existing item.
+	 *
+	 * @return Added / Updated {@link IBackpackItem}
+	 */
+	IBackpackItem addItem(ItemStack item);
+
+	/**
+	 * Removes an item from backpack.
+	 *
+	 * @return removed {@link IBackpackItem}, or null if not found.
+	 */
+	IBackpackItem removeItem(Material type);
+
+	/**
+	 * Sets the enchant level of given enchant
+	 *
+	 * @return removed {@link IBackpackItem}
 	 */
-	Map<Integer, Long> getEnchants();
+	boolean setEnchantLevel(BackpackEnchantment enchantment, long level);
 
 	/**
-	 * Returns Map
-	 * Key - {@link CompMaterial}
-	 * @return Map of backpack contents
+	 * Return the current enchant level
+	 *
+	 * @param enchantment {@link BackpackEnchantment}
+	 * @return current level of enchant
 	 */
-	Map<?, Long> getItems();
+	long getEnchantLevel(BackpackEnchantment enchantment);
 }
diff --git a/src/main/java/dev/drawethree/ultrabackpacks/api/model/backpack/IBackpackItem.java b/src/main/java/dev/drawethree/ultrabackpacks/api/model/backpack/IBackpackItem.java
new file mode 100644
index 0000000..2c4e848
--- /dev/null
+++ b/src/main/java/dev/drawethree/ultrabackpacks/api/model/backpack/IBackpackItem.java
@@ -0,0 +1,24 @@
+package dev.drawethree.ultrabackpacks.api.model.backpack;
+
+import org.bukkit.Material;
+
+public interface IBackpackItem {
+
+	/**
+	 * Gets the type of item.
+	 * @return {@link Material}
+	 */
+	Material getType();
+
+	/**
+	 * Gets the amount of item.
+	 * @return amount
+	 */
+	long getAmount();
+
+	/**
+	 * Sets the amount of item
+	 * @param amount amount
+	 */
+	void setAmount(long amount);
+}
diff --git a/src/main/java/dev/drawethree/ultrabackpacks/api/service/BackendAPI.java b/src/main/java/dev/drawethree/ultrabackpacks/api/service/BackendAPI.java
index e2dcd08..52b0b42 100644
--- a/src/main/java/dev/drawethree/ultrabackpacks/api/service/BackendAPI.java
+++ b/src/main/java/dev/drawethree/ultrabackpacks/api/service/BackendAPI.java
@@ -1,5 +1,6 @@
 package dev.drawethree.ultrabackpacks.api.service;
 
+import dev.drawethree.ultrabackpacks.api.exception.BackpackNotFoundException;
 import dev.drawethree.ultrabackpacks.api.model.backpack.IBackpackData;
 import org.bukkit.block.Block;
 import org.bukkit.entity.Player;
@@ -24,16 +25,18 @@ public abstract class BackendAPI {
 	 *
 	 * @param player Player
 	 * @return BackpackData.class
+	 * @throws BackpackNotFoundException if player has no backpack
 	 */
-	public abstract IBackpackData getBackpackData(Player player);
+	public abstract IBackpackData getBackpackData(Player player) throws BackpackNotFoundException;
 
 	/**
 	 * Sells the contents of player backpack.
 	 *
 	 * @param player  Player
 	 * @param sellAll If true, sells whole backpack. If false, sells only x amount of items based on AutoSell backpack enchant.
+	 * @throws BackpackNotFoundException if player has no backpack
 	 */
-	public abstract void sellBackpack(Player player, boolean sellAll);
+	public abstract void sellBackpack(Player player, boolean sellAll) throws BackpackNotFoundException;
 
 	/**
 	 * Handles the specified broken blocks and tries to add them into backpack