diff --git a/types.d.ts b/types.d.ts
index ec3250d..b5ce6c7 100644
--- a/types.d.ts
+++ b/types.d.ts
@@ -20,6 +20,7 @@ export interface MeasurementParamter {
 
 export interface Options {
   debug?: boolean;
+  userAgent?: string;
 }
 
 export class PageHit {