diff --git a/build.gradle.kts b/build.gradle.kts
index ecf732c..571e2a8 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -8,7 +8,7 @@ val githubActor = project.findProperty("gpr.user") as String? ?: System.getenv("
 val githubToken = project.findProperty("gpr.key") as String? ?: System.getenv("GITHUB_TOKEN")
 
 group = "me.tech"
-version = "0.0.8"
+version = "1.0.0"
 
 repositories {
     mavenCentral()
@@ -47,4 +47,4 @@ publishing {
             from(components["java"])
         }
     }
-}
+}
\ No newline at end of file
diff --git a/src/main/kotlin/me/tech/mcchestui/GUI.kt b/src/main/kotlin/me/tech/mcchestui/GUI.kt
index 2cd7f24..153792f 100644
--- a/src/main/kotlin/me/tech/mcchestui/GUI.kt
+++ b/src/main/kotlin/me/tech/mcchestui/GUI.kt
@@ -24,15 +24,8 @@ class GUI(
 	plugin: JavaPlugin,
 	val title: Component,
 	val type: GUIType,
-	rows: Int,
 	private val render: GUI.() -> Unit
 ): Listener {
-	@Deprecated(
-		message =  "Use allowPlaceItem instead.",
-		replaceWith = ReplaceWith("allowItemPlacement")
-	)
-	var allowShiftClicking: Boolean = false
-
 	/**
 	 * Allow for [ItemStack] to be placed in the [GUI].
 	 */
@@ -63,27 +56,13 @@ class GUI(
 	 */
 	var onCloseInventory: GUICloseEvent? = null
 
-	val rows =
-		if(type == GUIType.CHEST) {
-			rows
-			// We can assert this won't be null since the
-			// only null value is already checked.
-		} else {
-			type.rows!!
-		}
-
-	val inventory =
-		// Chest GUI.
-		if(type == GUIType.CHEST) {
-			plugin.server.createInventory(null, type.slotsPerRow * rows, title)
-			// Other GUi.
-		} else {
-			plugin.server.createInventory(null, type.inventoryType, title)
-		}
-
+	val inventory = if(type is GUIType.Chest) {
+		plugin.server.createInventory(null, type.slotsPerRow * type.rows, title)
+	} else {
+		plugin.server.createInventory(null, type.inventoryType, title)
+	}
 
-	// prevent user from inputting row amount for anything other than chest.
-	private var slots = arrayOfNulls<Slot>(type.slotsPerRow * this.rows)
+	private var slots = arrayOfNulls<Slot>(type.slotsPerRow * type.rows)
 
 	init {
 		plugin.server.pluginManager.registerEvents(this, plugin)
@@ -101,7 +80,7 @@ class GUI(
 	 */
 	fun refresh() {
 		inventory.clear()
-		slots = arrayOfNulls(type.slotsPerRow * rows)
+		slots = arrayOfNulls(type.slotsPerRow * type.rows)
 
 		this.render()
 	}
@@ -164,15 +143,15 @@ class GUI(
 
 		val x1 = 2
 		// Just makes it work with 1 row chest guis.
-		val y1 = if(type == GUIType.CHEST && rows == 1 || type == GUIType.HOPPER) 1 else 2
+		val y1 = if(type is GUIType.Chest && type.rows == 1 || type is GUIType.Hopper) 1 else 2
 
 		val x2 = type.slotsPerRow - 1
 		// Doesn't really matter if we hard code these values,
 		// what're they gonna do? Change? well besides chest guis.
 		val y2 = when(type) {
-			GUIType.CHEST -> if(rows > 2) rows - 1 else 2
-			GUIType.HOPPER -> 1
-			GUIType.DISPENSER -> 2
+			is GUIType.Chest -> if(type.rows > 2) type.rows - 1 else 2
+			is GUIType.Hopper -> 1
+			is GUIType.Dispenser -> 2
 		}
 
 		fill(x1, y1, x2, y2) {
@@ -186,7 +165,7 @@ class GUI(
 	 * @param builder slot builder.
 	 */
 	fun all(builder: Slot.() -> Unit) {
-		fill(1, 1, type.slotsPerRow, rows, builder)
+		fill(1, 1, type.slotsPerRow, type.rows, builder)
 	}
 	/**
 	 * Set the item of the next available slot not occupied by any item.
diff --git a/src/main/kotlin/me/tech/mcchestui/GUIHelper.kt b/src/main/kotlin/me/tech/mcchestui/GUIHelper.kt
index 0bb3c3b..deb5e66 100644
--- a/src/main/kotlin/me/tech/mcchestui/GUIHelper.kt
+++ b/src/main/kotlin/me/tech/mcchestui/GUIHelper.kt
@@ -4,24 +4,6 @@ import net.kyori.adventure.text.Component
 import org.bukkit.entity.HumanEntity
 import org.bukkit.plugin.java.JavaPlugin
 
-/**
- * Create a GUI.
- * Automatically sets the rows to 1.
- *
- * @param plugin
- * @param title Title of the GUI
- * @param type Type of GUI to generate
- * @return [GUI] Object
- */
-fun gui(
-	plugin: JavaPlugin,
-	title: Component,
-	type: GUIType,
-	render: GUI.() -> Unit
-): GUI {
-	return gui(plugin, title, type, 1, render)
-}
-
 /**
  * Create a GUI.
  *
@@ -35,10 +17,9 @@ fun gui(
 	plugin: JavaPlugin,
 	title: Component,
 	type: GUIType,
-	rows: Int,
 	render: GUI.() -> Unit
 ): GUI {
-	return GUI(plugin, title, type, rows, render).apply(render)
+	return GUI(plugin, title, type, render).apply(render)
 }
 
 /**
diff --git a/src/main/kotlin/me/tech/mcchestui/GUIType.kt b/src/main/kotlin/me/tech/mcchestui/GUIType.kt
index 4dd420e..83c9d40 100644
--- a/src/main/kotlin/me/tech/mcchestui/GUIType.kt
+++ b/src/main/kotlin/me/tech/mcchestui/GUIType.kt
@@ -8,12 +8,46 @@ package me.tech.mcchestui
 
 import org.bukkit.event.inventory.InventoryType
 
-enum class GUIType(
-	val inventoryType: InventoryType,
-	val slotsPerRow: Int,
-	val rows: Int?
-) {
-	CHEST(InventoryType.CHEST, 9, null),
-	DISPENSER(InventoryType.DISPENSER, 3, 3),
-	HOPPER(InventoryType.HOPPER, 5, 1);
+sealed interface GUIType {
+	 val slotsPerRow: Int
+	 val rows: Int
+	 val inventoryType: InventoryType
+
+	 data class Chest(override val rows: Int) : GUIType {
+		 override val slotsPerRow: Int
+			 get() = 9
+
+		 override val inventoryType: InventoryType
+			 get() = InventoryType.CHEST
+
+		 init {
+			 if(rows < 1 || rows > 6) {
+				 throw IllegalArgumentException(
+					 "chest rows cannot be ${if(rows < 1) "below" else "above"} $rows."
+				 )
+			 }
+		 }
+	 }
+
+	object Dispenser : GUIType {
+		override val slotsPerRow: Int
+			get() = 3
+
+		override val rows: Int
+			get() = 3
+
+		override val inventoryType: InventoryType
+			get() = InventoryType.DISPENSER
+	}
+
+	object Hopper : GUIType {
+		override val slotsPerRow: Int
+			get() = 5
+
+		override val rows: Int
+			get() = 1
+
+		override val inventoryType: InventoryType
+			get() = InventoryType.HOPPER
+	}
 }
\ No newline at end of file