diff --git a/admin/src/components/AddItemForm.tsx b/admin/src/components/AddItemForm.tsx
index d8c3253..e48247a 100644
--- a/admin/src/components/AddItemForm.tsx
+++ b/admin/src/components/AddItemForm.tsx
@@ -30,7 +30,7 @@ const AddItemForm: React.FC<AddItemFormProps> = ({ onClose, alert }) => {
             </Field.Root>
             <Field.Root>
               <Field.Label>Schließfachnummer (immer zwei Zahlen)</Field.Label>
-              <Input id="lockerNumber" placeholder="Nummer 01 - 06" />
+              <Input id="safe_nr" placeholder="Nummer 01 - 06" />
             </Field.Root>
             <Field.Root>
               <Field.Label>Ausleih-Berechtigung (Rolle)</Field.Label>
@@ -57,17 +57,16 @@ const AddItemForm: React.FC<AddItemFormProps> = ({ onClose, alert }) => {
                 (document.getElementById("can_borrow_role") as HTMLInputElement)
                   ?.value
               );
-              const lockerValue = (
-                document.getElementById("lockerNumber") as HTMLInputElement
+              const safeNrValue = (
+                document.getElementById("safe_nr") as HTMLInputElement
               )?.value.trim();
 
-              const lockerNumber =
-                lockerValue === "" ? null : Number(lockerValue);
+              const safeNr = safeNrValue === "" ? null : safeNrValue;
 
               if (!name || Number.isNaN(role)) return;
-              if (lockerNumber !== null && Number.isNaN(lockerNumber)) return;
+              if (safeNr !== null && !/^\d{2}$/.test(safeNr)) return;
 
-              const res = await createItem(name, role, lockerNumber);
+              const res = await createItem(name, role, safeNr);
               if (res.success) {
                 alert(
                   "success",
diff --git a/admin/src/utils/userActions.ts b/admin/src/utils/userActions.ts
index eb254a1..06974df 100644
--- a/admin/src/utils/userActions.ts
+++ b/admin/src/utils/userActions.ts
@@ -165,7 +165,7 @@ export const deleteItem = async (itemId: number) => {
 export const createItem = async (
   item_name: string,
   can_borrow_role: number,
-  lockerNumber: number | null
+  lockerNumber: string | null
 ) => {
   console.log(JSON.stringify({ item_name, can_borrow_role, lockerNumber }));
   try {
diff --git a/backendV2/schemeV2.sql b/backendV2/schemeV2.sql
index d434f5e..934ed5a 100644
--- a/backendV2/schemeV2.sql
+++ b/backendV2/schemeV2.sql
@@ -47,10 +47,6 @@ CREATE TABLE items (
   UNIQUE KEY ux_items_safe_nr (safe_nr)
 ) ENGINE=InnoDB;
 
-CREATE UNIQUE INDEX ux_items_safe_nr_not_null
-ON items (safe_nr)
-WHERE safe_nr IS NOT NULL;
-
 CREATE TABLE apiKeys (
   id INT NOT NULL AUTO_INCREMENT,
   api_key CHAR(8) NOT NULL UNIQUE,