diff --git a/src/types.ts b/src/types.ts
index ab6ceceb..daf194e3 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -21,7 +21,7 @@ export interface LayerProps {
   markerIcon: string,
   markerShape: string,
   markerDefaultColor: string,
-  markerDefaultColor2: string,
+  markerDefaultColor2?: string,
   api?: ItemsApi<any>,
   itemType: ItemType,
   itemNameField?: string,