diff --git a/types/extended-listbox/extended-listbox-tests.ts b/types/extended-listbox/extended-listbox-tests.ts
index dfa51ffebf..4d03ada74e 100644
--- a/types/extended-listbox/extended-listbox-tests.ts
+++ b/types/extended-listbox/extended-listbox-tests.ts
@@ -12,7 +12,7 @@ options.multiple = true;
 options.searchBar = false;
 options.searchBarWatermark = "Search";
 options.searchBarButton = { icon: "fa fa-search", visible: true, onClick: function () { alert(); } };
-options.getItems = function (): any[] {
+options.getItems = (): (string|ListboxItem)[] => {
     return ["Test1"];
 };
 options.onItemsChanged = (event: ListboxEvent): void => {
@@ -23,13 +23,13 @@ options.onItemsChanged = (event: ListboxEvent): void => {
 options.onFilterChanged = (event: ListboxEvent): void => {
     console.log(event.args);
 };
-options.onValueChanged = function (event: ListboxEvent): void {
+options.onValueChanged = (event: ListboxEvent): void => {
     console.log(event.args);
 };
-options.onItemDoubleClicked = function (event: ListboxEvent): void {
+options.onItemDoubleClicked = (event: ListboxEvent): void => {
     console.log(event.args);
 };
-options.onItemEnterPressed = function (event: ListboxEvent): void {
+options.onItemEnterPressed = (event: ListboxEvent): void => {
     console.log(event.args);
 };
 
@@ -39,7 +39,7 @@ instance = <ExtendedListboxInstance>$test.listbox(options);
 /////// NEW API ///////
 
 // Add string item
-var id = instance.addItem("Test2");
+var id: string = instance.addItem("Test2");
 
 
 // Add item
@@ -54,10 +54,18 @@ item.text = "Test3";
 id = instance.addItem(item);
 
 
+// Add string items
+var ids: string[] = instance.addItems(["Test2", "Test1"]);
+
+
 // Remove item
 instance.removeItem(id);
 
 
+// Remove items
+instance.removeItems([id, ids[0]]);
+
+
 // Get item
 var i: ListboxItem = instance.getItem(id);
 
diff --git a/types/extended-listbox/index.d.ts b/types/extended-listbox/index.d.ts
index 3f3527b903..b8495b2f94 100644
--- a/types/extended-listbox/index.d.ts
+++ b/types/extended-listbox/index.d.ts
@@ -1,4 +1,4 @@
-// Type definitions for extended-listbox 2.0.x
+// Type definitions for extended-listbox 3.0.x
 // Project: https://github.com/code-chris/extended-listbox
 // Definitions by: Christian Kotzbauer <https://github.com/code-chris>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
@@ -26,7 +26,7 @@ interface ListboxItem {
     parentGroupId?: string;
 
     /** list of childItems */
-    childItems?: any[];
+    childItems?: ListboxItem[];
 }
 
 interface ListboxSearchBarButtonOptions {
@@ -54,7 +54,7 @@ interface ListBoxOptions {
     multiple?: boolean;
 
     /** function which returns a array of items */
-    getItems?: () => any;
+    getItems?: () => (string|ListboxItem)[];
 
     /** callback for selection changes */
     onValueChanged?: (event: ListboxEvent) => void;
@@ -90,9 +90,15 @@ interface ExtendedListboxInstance {
     /** Adds a new item to the list */
     addItem(item: string|ListboxItem): string;
 
+    /** Adds new items to the list */
+    addItems(item: (string|ListboxItem)[]): string[];
+
     /** Removes a item from the list */
     removeItem(identifier: string): void;
 
+    /** Removes items from the list */
+    removeItems(identifiers: string[]): void;
+
     /** Reverts all changes from the DOM */
     destroy(): void;