diff --git a/src/elements/radio-button/radio-button-group/radio-button-group.ts b/src/elements/radio-button/radio-button-group/radio-button-group.ts
index 721d101a3f..1ba317ea14 100644
--- a/src/elements/radio-button/radio-button-group/radio-button-group.ts
+++ b/src/elements/radio-button/radio-button-group/radio-button-group.ts
@@ -55,7 +55,7 @@ class SbbRadioButtonGroupElement extends SbbDisabledMixin(LitElement) {
    * The value of the radio group.
    */
   @property()
-  public set value(val: any | null) {
+  public set value(val: string | null) {
     this._fallbackValue = val;
     if (!this._didLoad) {
       return;
@@ -69,13 +69,13 @@ class SbbRadioButtonGroupElement extends SbbDisabledMixin(LitElement) {
       toCheck.checked = true;
     }
   }
-  public get value(): any | null {
+  public get value(): string | null {
     return this.radioButtons.find((r) => r.checked && !r.disabled)?.value ?? this._fallbackValue;
   }
   /**
    * Used to preserve the `value` in case the radios are not yet 'loaded'
    */
-  private _fallbackValue: any | null = null;
+  private _fallbackValue: string | null = null;
 
   /**
    * Size variant, either xs, s or m.
diff --git a/src/elements/radio-button/radio-button-group/readme.md b/src/elements/radio-button/radio-button-group/readme.md
index c1c0f873c2..883b1ecdb6 100644
--- a/src/elements/radio-button/radio-button-group/readme.md
+++ b/src/elements/radio-button/radio-button-group/readme.md
@@ -80,7 +80,7 @@ In order to ensure readability for screen-readers, please provide an `aria-label
 | `radioButtons`        | -                       | public  | `(SbbRadioButtonElement \| SbbRadioButtonPanelElement)[]` |                                            | List of contained radio buttons.                          |
 | `required`            | `required`              | public  | `boolean`                                                 | `false`                                    | Whether the radio group is required.                      |
 | `size`                | `size`                  | public  | `SbbRadioButtonSize`                                      | `'m' / 'xs' (lean)`                        | Size variant, either xs, s or m.                          |
-| `value`               | `value`                 | public  | `any \| null`                                             |                                            | The value of the radio group.                             |
+| `value`               | `value`                 | public  | `string \| null`                                          |                                            | The value of the radio group.                             |
 
 ## Events
 
diff --git a/src/visual-regression-app/src/components/test-case/image-diff/fullscreen-diff/fullscreen-diff.ts b/src/visual-regression-app/src/components/test-case/image-diff/fullscreen-diff/fullscreen-diff.ts
index a8b39c1107..21bd1df563 100644
--- a/src/visual-regression-app/src/components/test-case/image-diff/fullscreen-diff/fullscreen-diff.ts
+++ b/src/visual-regression-app/src/components/test-case/image-diff/fullscreen-diff/fullscreen-diff.ts
@@ -11,6 +11,8 @@ import '@sbb-esta/lyne-elements/chip-label.js';
 import '@sbb-esta/lyne-elements/radio-button.js';
 import type { SbbRadioButtonGroupElement } from '@sbb-esta/lyne-elements/radio-button/radio-button-group/radio-button-group.js';
 
+export type DiffFileType = 'baselineFile' | 'failedFile' | 'diffFile';
+
 /**
  * Displays two images in fullscreen to overlay them.
  */
@@ -21,8 +23,7 @@ class FullscreenDiff extends LitElement {
 
   @property() public accessor screenshotFiles: ScreenshotFiles | null = null;
 
-  @property() public accessor selectedFile: 'baselineFile' | 'failedFile' | 'diffFile' =
-    'failedFile';
+  @property() public accessor selectedFile: DiffFileType = 'failedFile';
 
   public override render(): TemplateResult {
     if (!this.screenshotFiles) {
@@ -38,7 +39,7 @@ class FullscreenDiff extends LitElement {
         class="app-radio-button-group"
         value=${this.selectedFile}
         @change=${(event: Event) =>
-          (this.selectedFile = (event.target as SbbRadioButtonGroupElement).value)}
+          (this.selectedFile = (event.target as SbbRadioButtonGroupElement).value as DiffFileType)}
       >
         ${!this.screenshotFiles.isNew
           ? html`<sbb-radio-button value="baselineFile">Baseline</sbb-radio-button>`